im currently running a stock displacement m6 ls1 with an f14 cam, fast90/90, 36lb injectors, electric water pump, pulley, long tubes, basically all the bolt ons & an older set of ported 853 heads and a fresh custom tune.

i recently dynoed the car and and only got 385rwhp 345rwtq and im pissed.

the car has never really put down the numbers on the dynoe but runs like hell on the street. before this i had a 228/232 with an ls6 intake no pulley and stock water pump and put down 373rwhp and torque in the 330's.

i dont see how after adding the pulley, water pump, fast 90/90, and bigger(slightly) cam i was only able to gain about a peak of 13 hp & ftlbs even though low and mid range gains were more impressive (something like 20+ hp).

the only thing i can come up with is the motor is still running on the original timing chain and lifters and their probably getting tired and perhaps the heads arnt flowing enough to keap up with the cam. does anyone have any suggestions?

im thinking of upgrading the heads my current set up only flows in the mid 290's at .550-.600 lift. id like to stay at $1500-1600 or less for the heads fullly assembled; this with the timing chain and lifter im hoping to get her well over 400rwhp.

help me out guys i could use your input

 

they say that a 241 with tea stg 1 5.7 with stock valves will make 420 - 430hp with 400+ tq with a smaller cam for 999$ or so . no ****

 

they say that a 241 with tea stg 1 5.7 with stock valves will make 420 - 430hp with 400+ tq with a smaller cam for 999$ or so . no **** if the rest of your car is ok
maby you should take some time to look your car over first . if you get a good head
and dont make the power wast of $$$$

 

Might wanna check lifter preload and make sure everything is in tolerance? Unless the timing chain is broken, I'd assume it's fine. Maybe the FAST 90/90 is too much for you now until you get a good set of heads?

 

Yeah I'm betting you'd actually seen gains with an ls6 intake over the FAST setup.
That being said... get head

 

i just found out the current ported heads flow under 295cfm at .550 lift and even though the head was decked the chambers were releived so compression staid the same. the timing chain got a bit of slack in it. at this point im gonna assume the lifters need to be replaced after 50k of abuse.

im thinking of going with a set of 5.3 heads and take the CR to at least 11 to 1.

 

How well is your car tuned?
What is the AFR and Timing reading at WOT?

 

I would get the problem worked out before throwing new heads at it. You should be making at least 420 rwhp with the heads you have. They flow better than stock LS6 heads and people are making around 420 without the EWP and 90/90. BTW the 90/90 has been proven to make 12 rwhp on a stock Z06 cam and stock LS6 heads so don't believe this hurt your setup as some have stated.

 

You seem to have all the components that I have with the exception of heads. I'd suspect heads that aren't ported as well as promised. Everything else on your car is a known quantity. You should be making LOTS more power. Make sure you spend good money this time on heads...they are the key to your missing hp IMO.

 

i dont have the dyno graph with me but i was there when it was being dynoed and whatched him lean it out so im sure the AFR is right on and im not sure of the timing.
i finaly drove the car lastnight and it feels alot stronger from before i took it in and it ran strong then too.
the shop that dynoed it dynoes another SS before mine with nearly the same components exept for the water pump and pulley and that car put down 402rwhp with the same guy tuning it.

 

could the 3" exghaust be bottleing this car up so much as to cause this much loss?

 

It could be, but in my case, I gain 6 rwhp going from a catted y-pipe and 3" cutout to open headers with no cats. 3" exhaust may or may not be hurting you. I'd look into some better heads if you've eliminated all the other variables.

 

im gonna wait a little longer on the heads but change out the lifters and timing chain as well as take the exhaust up to 4" through a spin tech muffler and let someone else play with the tune and see wherethat gets me. there's quite a few new heads coming out later this year and i want to see em before i make up my mind.