I was wondering what some approximate max HP numbers were on ported lt1 heads. I put my car on the dyno and the tq and HP curve dropped off faster on nitrous than on motor so i was thinking my heads might be at their limit at around 550 at the rear on the juice. here are the flow numbers on my heads, they are identical to the GTP stg II heads
.200 .300 .400 .500 .600 .650
Intake 135.6 186.5 228.5 262 285.5 288.4
Exhaust 100.3 142.5 170.9 194.6 209.5 212

Thanks for any info/opinions

Chad

 

Ill change the question around a little, what are some peak HP/TQ numbers you all are pulling with similar heads to mine? I am just wondering if i should go with ported LT4's or AFr's or if i should stay with the heads I have. thanks

Chad

 

before I blew a head gasket, and had to replace my heads I peaked out at 415rwhp and about 380rwtq

 

I read somewhere that your max hp NA is the flow of your heads at max lift X 2, so if your cam maxes lift at .600 your max (this is for all ci, dont think that is thrown into the equation) is 285.5x2=571 NA hp. this is definitly not for a 350 ci motor though, this would be with a 427 or some bigger stroker.

 

I had read that formula in someones post also, i was hoping to clear somethings up on it though. I know its a very rough estimate, but is that HP reading at the rear wheels or flywheel? Also, what if you have a power adder, like nitrous? is the formula not useful, or could you figure it some other way? Does anyone want to take an educated guess as if i should go with a different head (ported AFR or LT4)according to my sig and dyno numbers: on motor it makes 336.2 HP (6200 RPM)and 457 RWTQ(3300RPM) and on the juice it makes 447.3 HP(5400RPM) and 549 RWTQ(3900RPM) dyno'ing through loose 4000 convertor, TH350, moser 12 bolt with 4.11's and 28inch tall slicks.

-Chad

 

557 FWHP with stock ported LT1 heads N/A. Max flow was around 290.

 

dont forget when you get to 500-600rwhp everything matters, especially exhaust/headers,elec waterpump,pullys, etc. i just put down 420rwhp with box comp port AFR 195's and im hoping to see 450+rwhp when i get them ported w/ a custom cam from joe overton. oh i dynoed 380rwhp w/ mail order tune and 2.5" ypipe. dyno tune + 3" ypipe = 40hp!!!

ive see ported 195's flow 300+ cfm @600 and put down 450rwhp on a stock bottomend car with a hyd roller