Anyone considered this head swap? [Archive] - Cherokee SRT8 Forum

: Anyone considered this head swap?


RAMM
03-07-2007, 09:52 AM
I was thinking that although the 6.1L HEMI is an amazing engine that although impressive in a 4200lb LX car that maybe it isn't the best candidate for a 4700-4800lb GC. I am willing to bet that a nicely set of ported 5.7 heads when bolted onto a 6.1L shortblock and mated with the GC platform would create pure magic! Just looking at the 6.1 heads and their flow of close to 300 cfm from the factory makes me think RACE head! for a RACECAR! There's a reason Dodge hasn't relinquished the 6.1 to truck duty yet. I was thinking that 5.7 heads when ported, regularly flow 300-315cfm which is still about 20-25cfm more than a factory 6.1 casting.
Hmm---much larger port 6.1L head=290-300cfm
---much smaller port 5.7L head ported=300-315cfm
The smaller the port with the same or better flow at the same valve lifts = VELOCITY!! Velocity= throttle response and TORQUE, which = awesome driveability and FUN FUN FUN! I would have a hard time believing that no one has tried this yet and would love to hear the results if anyone has. Like I said the 6.1 and 5.7 for that matter ARE amazing engines but I think the 6.1 is more race engine than truck engine and it was pure marketing that got them put under the hood of GC's. I am so convinced that this would be THE swap that I will be trying it on my own GC SRT-8 in the very near future.

gculver
03-07-2007, 10:02 AM
I was thinking that although the 6.1L HEMI is an amazing engine that although impressive in a 4200lb LX car that maybe it isn't the best candidate for a 4700-4800lb GC. I am willing to bet that a nicely set of ported 5.7 heads when bolted onto a 6.1L shortblock and mated with the GC platform would create pure magic! Just looking at the 6.1 heads and their flow of close to 300 cfm from the factory makes me think RACE head! for a RACECAR! There's a reason Dodge hasn't relinquished the 6.1 to truck duty yet. I was thinking that 5.7 heads when ported, regularly flow 300-315cfm which is still about 20-25cfm more than a factory 6.1 casting.
Hmm---much larger port 6.1L head=290-300cfm
---much smaller port 5.7L head ported=300-315cfm
The smaller the port with the same or better flow at the same valve lifts = VELOCITY!! Velocity= throttle response and TORQUE, which = awesome driveability and FUN FUN FUN! I would have a hard time believing that no one has tried this yet and would love to hear the results if anyone has. Like I said the 6.1 and 5.7 for that matter ARE amazing engines but I think the 6.1 is more race engine than truck engine and it was pure marketing that got them put under the hood of GC's. I am so convinced that this would be [B]THE [B]swap that I will be trying it on my own GC SRT-8 in the very near future.
Doing that steps the compression up into the 11's and some change(trouble on pump gas)The 5.7L pistons are dished,the 6.1L are flat. There is a few companies working on this very idea with a twist, but I'm not telling right now.

RAMM
03-07-2007, 10:05 AM
I was aware of the comp ratio increase and although it wouldn't be a true back to back test in my case as I was going to convert over to E85 (105 octane) at the same time. Should be a killer!

BuilderBill
03-07-2007, 11:03 AM
Doing that steps the compression up into the 11's and some change(trouble on pump gas)The 5.7L pistons are dished,the 6.1L are flat. There is a few companies working on this very idea with a twist, but I'm not telling right now.
Damn, this could get expensive!

Beast 2
03-07-2007, 07:33 PM
You have a great idea, but there are some things that need to be cleared up.

5.7 head +/- 80cc combustion chamber
6.1 head +/- 70cc combustion chamber

6.1 heads on a 5.7 raise compression (I have done this) and 5.7 heads on a 6.1 would lower comression IF THEY FIT.

You CAN make them work if you:
Machine the 5.7 heads to allow the clearance needed because the 6.1 piston comes out of the bore and would hit the head

OR

Run some custom thick Cometic head gaskets ($200 or more)

You will also need to port match the intakes on the 5.7 heads to fit the 6.1 manifold (no problem either I have done that too).

Also any 04-up 5.7 HEMI uses EGR in the pass side head. You can either find 2003 truck heads (not too hard to find) or just tap and plug the holes (I've done that too).

Also you MIGHT need 5.7 pushrods, but they are super cheap. I know when switching to 6.1 heads on a 5.7 we went to 6.1 pushrods, so the opposite swap might require the same. The 5.7 pushrods are shorter by a little bit.

Another thing to watch out for, the truck heads do not have the holes for the P/S pump on the pass side. It's an easy fix though.

gculver
03-07-2007, 08:24 PM
So clearancing the 5.7L combustion chamber to work on a 6.1L would lower static compression even further. I wasn't looking at it that way. Is the 5.7L piston flat top are dished(was going on word of mouth), how much of the 6.1L is outta the hole(10cc less or more?)

Beast 2
03-07-2007, 09:11 PM
The 5.7 is actaully domed. The 6.1 is flat top. I am not sure exactly how far out of the hole it comes, but I can ask my partner (he does all our engine design and assembly) or measure one.

gculver
03-07-2007, 09:49 PM
The 5.7 is actaully domed. The 6.1 is flat top. I am not sure exactly how far out of the hole it comes, but I can ask my partner (he does all our engine design and assembly) or measure one.
Was Just curious for furture reference. Does the Hemi shop have any plans on a new head casting on the lines of this discussion???.

Beast 2
03-07-2007, 10:10 PM
We could probably CNC a combustion chamber on the 5.7 that would work, however I bet our CNC 6.1 head would still outperform our CNC 5.7 head on a 6.1, we know it does on a 5.7.

GotStroke?
03-07-2007, 10:55 PM
I was thinking that although the 6.1L HEMI is an amazing engine that although impressive in a 4200lb LX car that maybe it isn't the best candidate for a 4700-4800lb GC. I am willing to bet that a nicely set of ported 5.7 heads when bolted onto a 6.1L shortblock and mated with the GC platform would create pure magic! Just looking at the 6.1 heads and their flow of close to 300 cfm from the factory makes me think RACE head! for a RACECAR! There's a reason Dodge hasn't relinquished the 6.1 to truck duty yet. I was thinking that 5.7 heads when ported, regularly flow 300-315cfm which is still about 20-25cfm more than a factory 6.1 casting.
Hmm---much larger port 6.1L head=290-300cfm
---much smaller port 5.7L head ported=300-315cfm
The smaller the port with the same or better flow at the same valve lifts = VELOCITY!! Velocity= throttle response and TORQUE, which = awesome driveability and FUN FUN FUN! I would have a hard time believing that no one has tried this yet and would love to hear the results if anyone has. Like I said the 6.1 and 5.7 for that matter ARE amazing engines but I think the 6.1 is more race engine than truck engine and it was pure marketing that got them put under the hood of GC's. I am so convinced that this would be THE swap that I will be trying it on my own GC SRT-8 in the very near future.

I don't think you're going to make more power. It seems quite a few people claim that the intake ports on the 6.1 heads are too large, but at right around 210cc (from what I've seen), that's really not the case.

RAMM
03-08-2007, 10:56 AM
I think the 6.1 heads are an awesome head, just not the best choice for a heavy truck. A 210 cc intake port volume is still considered med-large within the smallblock racing realm. As for the chamber and piston differences between the 6.1 vs 5.7 that is nothing a little creative machining and parts selection wouldn't take care of. I still say that a smaller CSA (Cross-sectional Area) port with around 300cfm @.500" would be a superior performing head in the GC. The result will be a more responsive, torquier, way more fun to drive vehicle, without giving up anything noticeable up top if giving up anything. Velocity makes computers happy as well as STREET vehicles. I'll either fill some 6.1 heads to achieve the results I'm after or start with some way cheaper and more plentiful 5.7 heads and develop them. IME it will pay off big.

Beast 2
03-08-2007, 11:50 AM
FWIW I come from the HEMI truck side of things, most of the fastest HEMI trucks in the country are running our heads.

The fastest N/A truck in the country has our 5.7 based 370" (6.1L) stroker with our CNC ported 6.1 "big chamber" heads, 6.1 intake and a 10.5:1 CR. He ran 12.7's a few weeks ago in Shreveport without any track prep to the truck which weighs a little over 5,000 pounds with him in it.

Here was the dyno progression on my truck:

5.7 block, cnc 5.7 heads, 6.1 intake 356
w/ stock 6.1 heads 336
w/ CNC 6.1 heads 368
6.1 short block, CNC 6.1 heads, 6.1 intake 391 (with horrible tune)

When you put the 6.1 heads on a 5.7 the CR goes up about 1.6 points. Rational thinking would say that 5.7 heads on a 6.1 would drop compression about 1.6 points, from 10.3 down to 8.7 and if you used the thicker gaskets for the clearance issue you might go as low as 8.5:1.

I would think that drop in compression would offset any gains from increased airspeed.

GotStroke?
03-08-2007, 12:17 PM
I think the 6.1 heads are an awesome head, just not the best choice for a heavy truck. A 210 cc intake port volume is still considered med-large within the smallblock racing realm. As for the chamber and piston differences between the 6.1 vs 5.7 that is nothing a little creative machining and parts selection wouldn't take care of. I still say that a smaller CSA (Cross-sectional Area) port with around 300cfm @.500" would be a superior performing head in the GC. The result will be a more responsive, torquier, way more fun to drive vehicle, without giving up anything noticeable up top if giving up anything. Velocity makes computers happy as well as STREET vehicles. I'll either fill some 6.1 heads to achieve the results I'm after or start with some way cheaper and more plentiful 5.7 heads and develop them. IME it will pay off big.

You're preaching to the choir about velocity and keeping ports small. However IMO your numbers are off, 210cc is not too large for 370CI. I also say that prematurely limiting the amount of flow to 300cfm@.500 without velocity numbers makes zero sense. Wouldn't you rather have 320-330cfm at the same lift with like or better velocity?
I've seen good results from filling a 222cc Modular B head on a 4.6L (281CI) for good reason, the port volume is insanely high for such a small motor. In this case, again, the differences are not that drastic.
Best of luck with an interesting experiment, fwiw.

RAMM
03-08-2007, 04:30 PM
FWIW I come from the HEMI truck side of things, most of the fastest HEMI trucks in the country are running our heads.

The fastest N/A truck in the country has our 5.7 based 370" (6.1L) stroker with our CNC ported 6.1 "big chamber" heads, 6.1 intake and a 10.5:1 CR. He ran 12.7's a few weeks ago in Shreveport without any track prep to the truck which weighs a little over 5,000 pounds with him in it.

Here was the dyno progression on my truck:

5.7 block, cnc 5.7 heads, 6.1 intake 356
w/ stock 6.1 heads 336
w/ CNC 6.1 heads 368
6.1 short block, CNC 6.1 heads, 6.1 intake 391 (with horrible tune)

When you put the 6.1 heads on a 5.7 the CR goes up about 1.6 points. Rational thinking would say that 5.7 heads on a 6.1 would drop compression about 1.6 points, from 10.3 down to 8.7 and if you used the thicker gaskets for the clearance issue you might go as low as 8.5:1.

I would think that drop in compression would offset any gains from increased airspeed.

First of all thank you for sharing your experiences concerning the new HEMI and all of its iterations. I am not as nearly interested in peak HP numbers as I am with area under the curve. I'm sure that your heads are highly developed and impressive just as I am sure that they are more race oriented than street. I am also quite sure that with those 6.1 heads bolted on that the impressive HP gain came at the expense of low end torque. What does the port volume wind up at post porting on the 6.1 heads anyways? I'm truly not arguing the fact that your heads work--I mean c'mon almost mid 12's in a 5000+lb truck is impressive in anyone's book. As for the changes in compression ratio by swapping heads you I'm not sure I follow you:confused: Static compression ratio cannot change linearly as you state 1.6 one way or the other. It is much harder to build compression with a smaller cubic inch engine than it is a larger one because the swept volume has a bigger influence than chamber size. Either way compression will only go up 1.2 points with 6.1 heads on a 5.7 shortblock vs a drop of .8 with unaltered 5.7 heads on a 6.1 shortblock.
GotStroke?--My numbers concerning flow vs CSA are completely arbitrary. I was using them as a mental model or analogy if you will. Maybe a slightly better definition of a great port could be expressed as CFM per CC. A great head will be in the 1.5-1.52 range. (1.5x200=300-304) But then again the whole valvelift vs. flow factor needs to be considered.
To sum up--Perhaps the miscommunication stems from the universally differring opinions on what the true definition of a STREET/DAILY DRIVER is. I myself hate "waiting" for the RPM to come up get moving--And I love having massive amounts of "tip-in" power. Thank you for sharing your experience here it's what makes these forums great.:)

392Stu
03-08-2007, 06:17 PM
I think the 6.1 heads are an awesome head, just not the best choice for a heavy truck. A 210 cc intake port volume is still considered med-large within the smallblock racing realm. As for the chamber and piston differences between the 6.1 vs 5.7 that is nothing a little creative machining and parts selection wouldn't take care of. I still say that a smaller CSA (Cross-sectional Area) port with around 300cfm @.500" would be a superior performing head in the GC. The result will be a more responsive, torquier, way more fun to drive vehicle, without giving up anything noticeable up top if giving up anything. Velocity makes computers happy as well as STREET vehicles. I'll either fill some 6.1 heads to achieve the results I'm after or start with some way cheaper and more plentiful 5.7 heads and develop them. IME it will pay off big.

I understand where you are coming from and have heard it from quite a few people but I just don't see it in practice.

Beast2 and I have tried quite a few combos on both the 6.1 and 5.7 blocks. From several different dyno runs and more track/street time we are seeing that on a typically modded 6.1 cammed engine the 6.1 head is making 10-15 more lb-ft of torque than the 5.7 head throught the rpm range that can be tested on a chassis dyno. So from about 3500 RPM up. Not sure under that but the butt dyno tells me the 6.1 heads aren't short on torque either. The 12's N/A truck that Beast2 mentioned made 434 TQ @ 4600 RPM and 410 TQ @ 4000 RPM rear wheel through a truck driveline. Last time out it had a 1.76 sixty foot and a 8.08 1/8 mi. In short it did it all with torque. I designed it that way because the 03 truck pcm/tcm won't allow shifts any higher than 6000 RPM. It's definatley not a race only combo. It's a tire manufacturers wet dream:)

Although 210 CC is big for a small block chevy and would make a low end turd on a 370 ci chevy wedge engine, comparing intake volume of different engines is not accurate because you can have a small cross section and a long runner and have a large volume but it's just different because of the engine archetecture. On an engine with a long runner 210 could be a small port. Which leads into velocity. The distribution of velocity through the cross section of the port is more important than an average velocity number that you always hear and the Hemi weather 5.7 or 6.1 has a very consistant distribution because it's a real straight extremely raised port which allows for a more consistent cross section. This is in part because you don't have to slow the air down as much to make the bend like you do to get an efficient port on most wedge engines (same reason raised port heads make better torque and flow bigger low and mid lift numbers on wedge motors). This means that there is less dead air in the port, less turbulence and a more consistent fuel mix.

Velocity is also more a consideration in a carbed engine because of wet flow fuel atomization issues on an injected engine the fuel is sprayed on the back of the intake valve so you don't have near as much problem with fuel falling out of suspension and puddling as you do with a carb.

Well thats the theoretical flow bench racing explination, just touching some ideas, not that I have a dog in the fight because if the 5.7 heads performed better I would use them more but I am just not seeing it in the testing that I have done. It's also hard to argue with 434 RWTQ through a truck driveline which is giving up close to 25%. Thas around 580 at the crank which is built 540 big block chevy territory.

Beast 2
03-08-2007, 06:39 PM
^^^^ Yeah this conversation was headed beyond my expertise so I called in the big gun! Stu is my partner in the shop and he does all of our "technical" work and engine design/assembly. I just take his magic and bolt it in and make it run.

gculver
03-08-2007, 07:07 PM
So, I guess from now on, Instead of STU, I'll call him the "Magic Man". LOL . Also, since we have had our hands slapped for using the Shops name, I will have to speak in code </>++!!</>. Hope this works for us. BTW, I will be calling soon,this is the number right: 1-*%$& - ### - &^%#:D

392Stu
03-08-2007, 08:40 PM
So, I guess from now on, Instead of STU, I'll call him the "Magic Man". LOL . Also, since we have had our hands slapped for using the Shops name, I will have to speak in code </>++!!</>. Hope this works for us. BTW, I will be calling soon,this is the number right: 1-*%$& - ### - &^%#:D

I guess thats better than some of the things I've been called:)

RAMM
03-09-2007, 09:06 AM
I understand where you are coming from and have heard it from quite a few people but I just don't see it in practice.

Beast2 and I have tried quite a few combos on both the 6.1 and 5.7 blocks. From several different dyno runs and more track/street time we are seeing that on a typically modded 6.1 cammed engine the 6.1 head is making 10-15 more lb-ft of torque than the 5.7 head throught the rpm range that can be tested on a chassis dyno. So from about 3500 RPM up. Not sure under that but the butt dyno tells me the 6.1 heads aren't short on torque either. The 12's N/A truck that Beast2 mentioned made 434 TQ @ 4600 RPM and 410 TQ @ 4000 RPM rear wheel through a truck driveline. Last time out it had a 1.76 sixty foot and a 8.08 1/8 mi. In short it did it all with torque. I designed it that way because the 03 truck pcm/tcm won't allow shifts any higher than 6000 RPM. It's definatley not a race only combo. It's a tire manufacturers wet dream:)



Although 210 CC is big for a small block chevy and would make a low end turd on a 370 ci chevy wedge engine, comparing intake volume of different engines is not accurate because you can have a small cross section and a long runner and have a large volume but it's just different because of the engine archetecture. On an engine with a long runner 210 could be a small port. Which leads into velocity. The distribution of velocity through the cross section of the port is more important than an average velocity number that you always hear and the Hemi weather 5.7 or 6.1 has a very consistant distribution because it's a real straight extremely raised port which allows for a more consistent cross section. This is in part because you don't have to slow the air down as much to make the bend like you do to get an efficient port on most wedge engines (same reason raised port heads make better torque and flow bigger low and mid lift numbers on wedge motors). This means that there is less dead air in the port, less turbulence and a more consistent fuel mix.

Velocity is also more a consideration in a carbed engine because of wet flow fuel atomization issues on an injected engine the fuel is sprayed on the back of the intake valve so you don't have near as much problem with fuel falling out of suspension and puddling as you do with a carb.

Well thats the theoretical flow bench racing explination, just touching some ideas, not that I have a dog in the fight because if the 5.7 heads performed better I would use them more but I am just not seeing it in the testing that I have done. It's also hard to argue with 434 RWTQ through a truck driveline which is giving up close to 25%. Thas around 580 at the crank which is built 540 big block chevy territory.

Can't argue with those kind of torque numbers can I? Although the torque converter generally has a huge impact on chassis dyno torque numbers. I understand that the 5.7 heads have an extremely high velocity port with no dead spots. I have observed engine dyno test results that indicate the 6.1 engine being a little soft in the lower ranges (under 3500). I have no doubt that the 6.1 heads perform well at the strip--but then again horsepower rules the dragstrip in most cases. I guess what I'm still asking is-Can the 6.1 be improved for street/daily driver duty? Would the addition of "prepped" 5.7 heads make the 6.1 feel even more like a big block? Thanks for the indepth explanation I am convinced that your heads will be the ones to get when I build a 7.0 stroker--Now that should be one awesome ride.

392Stu
03-09-2007, 09:44 AM
I know the stock SRT8's are a bit soft on the launch. I think it's more weak gear and converter. I'm not certain whats happening before 3500 because the chassis dynos we use can't go any lower. We have been running an edge 2800 stall converter in most cases but I'm not convinced that it's much help. I think Brad is going to go back to a stock converetr in his truck and well see what happens to the 60 foot.

Personally I think that comp 268 cam is great for torque and that may be the ticket for the bottom end you are looking for. The heads don't loose any torque but the gains don't aren't too big until after 4000 RPM.

I did crunch some numbers on compression. The 5.7 heads are right at 85cc and the 6.1's are right at 72 cc they are pretty consistent unlike many older heads. If you put a 5.7 head on a 6.1 block you would get a 9.2 CR. The problem is the 6.1 piston has a 0.010" positive deck and the smaller chamber may not clear the piston because of the 0.040" gasket yeilding possibly only 0.030" of piston to head clearance. If you went to an 0.055" gasket to get 0.045" of clearance which would be safe you get a 9.0 CR. It's possible that the crown of the piston is small enough to fit in the 5.7 chamber with is approx 4.00" but I doubt it you would need to check real close. I think the best bet if you wanted to try a 5.7 head would be to completely mill the open chamber part of the head away (If theres enough meat in the head to take 0.055" being milled off, I'm not sure) creating a closed chamber and then run an 0.052" thick cometic gasket to give a real quench head an 0.042" worth of quench. This would reduce the 5.7 chamber volume to approxametly 73 cc which is very close to the 6.1 volume with the 0.052 thick gasket you would still be a little down on the stock 6.1 CR but not much. If you put larger valves in the heads you can reduce the chamber size another 1.5 cc's. Essentially the valves will be 0.040" closer to the pistons so you would want to check valve to piston clearance because thats real close on 6.1's already. But I think it would fly with a comp 268 cam.

Just an idea.

GRNENVY
03-09-2007, 02:20 PM
Remember ported cylinder heads are only as good as the porter doing the work. I have seen a ton of heads that looked great but just didn't perform on certain engines do to the combo. With this truck and the cam shaft style your low lift number are way more impotant then total flow at 600 or 650. I would try to acheive the highest possible air flow numbers at 200-300-400-500 lift that is way more important. I would also then send the upper and lower intake manifold to extrude hone for finishing touches. Oh and of course a set of high quality stepped heads once again trying to make tq. Any time you are successful in making tq the hp is usually right behind.
My two cents.

GotStroke?
03-09-2007, 03:17 PM
Remember ported cylinder heads are only as good as the porter doing the work. I have seen a ton of heads that looked great but just didn't perform on certain engines do to the combo. With this truck and the cam shaft style your low lift number are way more impotant then total flow at 600 or 650. I would try to acheive the highest possible air flow numbers at 200-300-400-500 lift that is way more important. I would also then send the upper and lower intake manifold to extrude hone for finishing touches. Oh and of course a set of high quality stepped heads once again trying to make tq. Any time you are successful in making tq the hp is usually right behind.
My two cents.

You mean mid lift is the most important, the piston is still moving the wrong way in the cylinder at low lift. Also Extrude Honing is not the way to port anything simply because it removes the same amount of material from everything it touches. Granted you're going to have to cut the stocker in half to hand port it, but the results will be better. Finally, stepped headers really only shine in race applications or motors with a very narrow power band.

GRNENVY
03-10-2007, 06:36 AM
LOL
I don't need an education on motors and build ups. I have had plenty 8,9 10sec cars in my time. I raced in renegade years ago with great results. So before you respond Yes I know Al very well best mod guy in the buisness. I'm great friends and hang with Horse power by Herman here in Tampa which does all my tuning on my 9 sec 03 cobra. As for Extrude Hone and stepped headers lets not go there. But good luck




You mean mid lift is the most important, the piston is still moving the wrong way in the cylinder at low lift. Also Extrude Honing is not the way to port anything simply because it removes the same amount of material from everything it touches. Granted you're going to have to cut the stocker in half to hand port it, but the results will be better. Finally, stepped headers really only shine in race applications or motors with a very narrow power band.

GotStroke?
03-10-2007, 12:40 PM
LOL
I don't need an education on motors and build ups. I have had plenty 8,9 10sec cars in my time. I raced in renegade years ago with great results. So before you respond Yes I know Al very well best mod guy in the buisness. I'm great friends and hang with Horse power by Herman here in Tampa which does all my tuning on my 9 sec 03 cobra. As for Extrude Hone and stepped headers lets not go there. But good luck


Owning a fast car means nothing. I can rip off a list of a dozen racers with single digit cars that can't change their own oil. Al is a great guy and bar none the best in the game, however your statements about low lift, EHing, and stepped headers are incorrect--Al will tell you the same. Take it how you will.

GRNENVY
03-10-2007, 12:43 PM
LOL
Like I said good luck

Owning a fast car means nothing. I can rip off a list of a dozen racers with single digit cars that can't change their own oil. Al is a great guy and bar none the best in the game, however your statements about low lift, EHing, and stepped headers are incorrect--Al will tell you the same. Take it how you will.

GotStroke?
03-10-2007, 12:46 PM
Same to you.

ps: http://www.rehermorrison.com/techTalk/16b.htm

Explains why low lift means nothing, but let me guess, you're great friends with the guys at Reher Morrison as well, LOL.

GotStroke?
03-10-2007, 12:49 PM
The GM of Stainless Works on stepped vs. non stepped headers:


Stepped headers typically “can” work well, from our experience, on an engine with no backpressure (open headers) that has a narrow RPM band that it needs to make peak power at. The reason I say can is because it really depends on the camshaft, cylinder head, rpm range-it is very application specific. In our experience on a street car with full exhaust, the cost increase in building a stepped header is not justified by the very small power gains you “may” see.

GotStroke?
03-10-2007, 12:50 PM
As for EHing, I'm sure you have Al's cell (if not send me a PM) just give him a yell. I'm thinking based on your choice in cars, and the classes you claim to have participated in, that you're predominantely a forced induction guy? Which may explain why you think EHing isn't so bad.
The thing is FI is an outstanding band aid when it comes to masking the inherent flaws of any motor. Too much runner volume/CS is easily compensated for with boost, even though it's still not optimal. N/A however is a completely different story.

GRNENVY
03-10-2007, 01:21 PM
So your saying 300-400-500 lift number's don't mean anything if you are your crazy and don't know ****. I know when I had Ron at Fox Lake build and port one of the first Victor jr heads off the assembly line for my renegade car thats all we looked at. My cam was limited to .500 lift and the heads were ported so they could flow the best they could below those numbers. My car was running mid 9s back in the mid 90s with a vortech with an AOD. Go pick up an old M/M mag you will see a green convertable in there thats me. (GRNENVY) As for forced induction I had a 347 all motor running faster times then most cars with power adders. Like I said before the right combination is where its at.
Cracks me up how some guys love to through names around.

This is my last post fighting with you about stupid ****
Good luck


UOTE=GotStroke?]As for EHing, I'm sure you have Al's cell (if not send me a PM) just give him a yell.[/QUOTE]

GotStroke?
03-10-2007, 01:26 PM
So your saying 300-400-500 lift number's don't mean anything if you are your crazy and don't know ****. I know when I had Ron at Fox Lake build and port one of the first Victor jr heads off the assembly line for my renegade car thats all we looked at. My cam was limited to .500 lift and the heads were ported so they could flow the best they could below those numbers. Oh and my car was running mid 9s back in the mid 90s with a vortech with an AOD.
People like you love to through big names around and talk **** on the net nothing new. This is my last post wasting my time. :D :D

UOTE=GotStroke?]As for EHing, I'm sure you have Al's cell (if not send me a PM) just give him a yell.

No, .300-500 is mid lift, not LOW lift.

BTW, Ron Robart doesn't do any porting/work, you should have thanked Corey Roth for your heads.

Do you find it at least a little bit ironic that you were the first person to mention names--with zero relevance to anything in this thread I might add: So before you respond Yes I know Al very well best mod guy in the buisness. LMAO

Congratulations on running 9s with a supercharged windsor, lol, we all know how hard that is. Did I hit the nail on the head with the FI comment or what?

Quite honestly the only one running their mouth, so to speak, is you. I've backed my statements, you continue to spew drivel. Have a nice day Mr. Credit Card Racer.

GRNENVY
03-10-2007, 01:33 PM
98Cobra Boss 333,AL 5.5l N/A DOHC come on thats to funny
We know who the bench racer is
OK I'm finished

No, .300-500 is mid lift, not LOW lift.

Do you find it at least a little bit ironic that you were the first person to mention names--with zero relevance to anything in this thread I might add: LMAO

Congratulations on running 9s with a supercharged windsor, lol, we all know how hard that is. Did I hit the nail on the head with the FI comment or what?

Quite honestly the only one running their mouth, so to speak, is you. I've backed my statements, you continue to spew drivel. Have a nice day Mr. Credit Card Racer.

GotStroke?
03-10-2007, 01:41 PM
98Cobra Boss 333,AL 5.5l N/A DOHC come on thats to funny
We know who the bench racer is
OK I'm finished

Ever heard of "projecting?"

I don't get it? My sig. says Boss 330 (as in Al built), aluminum 5.5L N/A DOHC....Hilarious...:confused:
If you're trying to figure out if I'm competent enough to build motors, yes I've built a few. Am I pompous enough to believe I can duplicate the work of a world class engine builder? Hell no. Of course this is after you boast about having work done by Fox Lake, HP by Herman, etc. so you have no argument whatsoever.
The simple fact is any jackass can make 1000HP with a blower/turbo, so don't feel too special.

392Stu
03-13-2007, 09:32 AM
Same to you.

ps: http://www.rehermorrison.com/techTalk/16b.htm

Explains why low lift means nothing, but let me guess, you're great friends with the guys at Reher Morrison as well, LOL.

Thats interesting, the guys that do our Hemi heads did the heads for Reher Morrison throught the late 70's, 80's and into the early 90's before starting their own shop. This is back in the Lee Sheapard days, when Reher morrison made their name and and won all the pro stock championships. They left in like 91 or 92 to open up there own shop if that tells you anything.

When they were doing our hemi design they actually reduced the flow at 0.200 and 0.300" lift a bit becuase the hemi head is real bad about passing fuel out the exhaust port. This is also the reason that hemi cams tend to run a wide LSA. This is more of a hemi specific issue and is not the same on wedge heads.

GotStroke?
03-13-2007, 11:07 AM
The piston is still moving the wrong way in the cylinder at low lift.

392Stu
03-13-2007, 12:05 PM
The piston is still moving the wrong way in the cylinder at low lift.

Most of the performance cams out there for the new hemi start to open the intake valve around 20 degrees before TDC when installed straight up. So with these cams the valve is only around 0.070" open at TDC this will change depending on the cam and how it's installed but this is the case for most of the cams that I have checked that are around the Comp 268 or a bit bigger.

One thing is for sure, with a stock piston SRT8 engine you won't be opening the valves much sooner than that. Theres only about 0.110" of valve free drop on the 6.1 engine. Take that and look at some of the existing cams and ponder if there is a problem with some of the existing settups.