Dynamometer Results & Comparisons - Did I max out my heads??




View Full Version : Did I max out my heads??


383ss
09-25-2005, 09:08 AM
I finally got my new cam installed and dyno'd. was expecting a ~10rwhp gain and the powerband moved up some...

blue line is old FMS 246/250 .632 110+4
red line is new FMS 253/261 .642 110+4

how did my power band not move up?? and why are they identical from 4500+? I'm guessing my heads are maxed out, but had not seen anyone post anything like it before.

my heads are 5.7L milled .031, 2.02 intake 1.57 exhaust.

flow #'s
lift; intake; exhaust
.100 70 54
.200 149 110
.300 218 154
.400 264 197
.500 286 222
.550 292 228
.600 293 233

http://mofbody.com/john/246-250vs253-261.jpg



here it is with a 100 TNT wet shot

http://mofbody.com/john/100TNT.jpg


Ben R
09-25-2005, 12:58 PM
I think so.

I would recommend a set of ET Performance 240CC cylinder heads for your application. Let me know if you're interested. I can get you some pricing and availability information.

383ss
09-25-2005, 01:59 PM
I think so.

I would recommend a set of ET Performance 240CC cylinder heads for your application. Let me know if you're interested. I can get you some pricing and availability information.


thanks, I had been emailing Craig @ ET Performance about them and what I need. I'll get in contact with you when I decide to order.


52172
09-25-2005, 02:31 PM
550/535 are still some very stout numbers through ls1 castings!! I wonder what you would put down with the ET heads? Could pick up another 30 rwhp!

Ben R
09-25-2005, 03:45 PM
thanks, I had been emailing Craig @ ET Performance about them and what I need. I'll get in contact with you when I decide to order.

Sounds good.

383ss
09-25-2005, 04:48 PM
550/535 are still some very stout numbers through ls1 castings!! I wonder what you would put down with the ET heads? Could pick up another 30 rwhp!
I would expect to be close to 600rwhp. this is a hydraulic cam also.
the 265's flow 21 more at 400, 38 more at .500, and 58 more at .600 than mine.

Ben R
09-25-2005, 05:09 PM
You could expect to see some rather large gains with a really set of cylinder heads. Those ET heads will flow 350 @ .650 with a 4.030 bore. With 50 more CFM of air you will see a VERY nice power increase.

52172
09-25-2005, 05:49 PM
I don't think I have seen anyone break 555 rwhp with a 408 ever!! Be the first one!

BlueSix
09-25-2005, 06:04 PM
I don't think I have seen anyone break 555 rwhp with a 408 ever!! Be the first one!

http://ls1tech.com/forums/showthread.php?t=244034

It's been done (at least) once before, and that was through a very heavy drivetrain. I think it's kinda funny that the most powerful 408's come from FMS.

Ben R
09-25-2005, 06:06 PM
It's all in the cylinder heads. Now that companies like ET offer kickass cylinder heads for large stroker engines I think we'll start to see more 550HP 408's and such.

383ss
09-25-2005, 07:09 PM
I don't think I have seen anyone break 555 rwhp with a 408 ever!! Be the first one!
highest hydraulic that FMS has done did 568. most seem to do in the 520-530 range.

I'm going to have these heads hogged out and put in 2.08 valves and see what it does. then I'll go to some ET heads :)

Nate_Taufer
09-25-2005, 07:55 PM
http://ls1tech.com/forums/showthread.php?t=244034

It's been done (at least) once before, and that was through a very heavy drivetrain. I think it's kinda funny that the most powerful 408's come from FMS.


I believe he is probably talking about pump gas. 14:1 compression 280+ duration cam on c16 isn't really all that streetable unless you own a race track and drive to work :D

Nate

52172
09-25-2005, 09:07 PM
Thats right I should have worded it differently, but I was referring to pump gas hydraulic roller cams.

52172
09-25-2005, 09:18 PM
why would you want to put more money into your ls1 heads when you can put that money towards the new ET heads?

383ss
09-25-2005, 10:41 PM
why would you want to put more money into your ls1 heads when you can put that money towards the new ET heads?

because I can.

ONEBADWS6
09-26-2005, 12:23 AM
I'm looking forward to the E.T heads, but the question is is what intake are we going to use to get all the cfm into the motor? A ported FAST 90 is good for 284cfm, a ls6 is good for 260cfm. So whats the point of 350cfm if we'll never see it?

52172
09-26-2005, 07:50 AM
wait for the ET manifold I guess should be at the PRI show. Coming out next year. Or buy ET's ls7 heads and run the ls7 intake.

383ss
09-26-2005, 11:06 AM
I'm looking forward to the E.T heads, but the question is is what intake are we going to use to get all the cfm into the motor? A ported FAST 90 is good for 284cfm, a ls6 is good for 260cfm. So whats the point of 350cfm if we'll never see it?

good point.

Patrick G
09-26-2005, 11:27 AM
I'm looking forward to the E.T heads, but the question is is what intake are we going to use to get all the cfm into the motor? A ported FAST 90 is good for 284cfm, a ls6 is good for 260cfm. So whats the point of 350cfm if we'll never see it?Better cylinder heads will make more power, even with a restrictive intake manifold. Why do you think NASCAR restrictor plate motors run the highest flowing cylinder heads they can find? Because they STILL make more power.

Ben R
09-26-2005, 11:32 AM
Better cylinder heads will make more power, even with a restrictive intake manifold. Why do you think NASCAR restrictor plate motors run the highest flowing cylinder heads they can find? Because they STILL make more power.

Just what I was going to say...

383ss
09-26-2005, 01:16 PM
I don't doubt the ET's would make quite a bit more power, but it is still going to be restricted by the intake.

Got Me SOM
09-26-2005, 01:50 PM
why not run the gmpp single plane intake with the et heads?

52172
09-26-2005, 03:37 PM
why not just run your hogged out ls1 castings until their new intake is available next summer then purchase the ET heads?????? Sounds like a plan to me.

Brandon Boomhauer
09-26-2005, 03:40 PM
Better cylinder heads will make more power, even with a restrictive intake manifold. Why do you think NASCAR restrictor plate motors run the highest flowing cylinder heads they can find? Because they STILL make more power.exactly:judge:
I'm planning on a set of ET heads for mysetup, I'll probably be on a fast with them for awhile, unless their new intake hits the shelves within 6 months....

52172
09-26-2005, 03:42 PM
I talked to cary and craig today and they said the intake will not be ready until summer next year it will however be released at the PRI show.

VINCE
09-26-2005, 03:47 PM
Very stout numbers guys. The highest I have made is 563rwhp with my 408ci.

Ben R
09-26-2005, 03:50 PM
I don't doubt the ET's would make quite a bit more power, but it is still going to be restricted by the intake.

Think about it like this.

The FAST manifold is already a restriction, why would you want another restriction (I.E. crappy heads) in the equation. You've already got one part holding you back, why would you want two?

383ss
09-26-2005, 05:34 PM
Think about it like this.

The FAST manifold is already a restriction, why would you want another restriction (I.E. crappy heads) in the equation. You've already got one part holding you back, why would you want two?
I just want to see what I can get out of the 5.7's first. hell, I already have them sold, I just want to see. I think I can get close to 9's on motor.

PHIL H
09-26-2005, 08:37 PM
because I can.

You sending them back to CHS to get redone?

383ss
09-26-2005, 10:32 PM
You sending them back to CHS to get redone?


yep. he thinks he can get 20more rwhp out of them.

PHIL H
09-26-2005, 10:33 PM
yep. he thinks he can get 20more rwhp out of them.

He's the man!! Hope it works out for you.

52172
09-27-2005, 08:03 AM
who is CHS he must kick some ass at porting heads as those are some very stout numbers even for stage three ls6 heads.

PHIL H
09-27-2005, 09:09 AM
who is CHS he must kick some ass at porting heads as those are some very stout numbers even for stage three ls6 heads.

Yes he does excellent work at a way affordable price. And if i remember correctly they are regular 5.7 heads not LS6 castings.

383ss
09-27-2005, 03:36 PM
yes, my current heads are 5.7L with 2.02/1.57 valves!

chs is not a sponsor, so if you want the web site, I guess you'll have to PM me. they are very good heads for a great price