Corr1

Hi Guys...Newbie here.
This is what I have:
91lx 347 NA, C4-4200 stall with transbrake, 4.10,s, welds with skinny's and 9" slicks, Eibach front and back springs with drag launch kit, subframe and uppers and lowers non-adj installed.
Engine: 347 with 10.3-1 comp, edlel pro Rpm 170cc(I think), airgap intake, QF 750 with man secondary, bbk shorty's with h-pipe, no mufflers.

I launch at 3400 rpm, best time ever was a 11.91 at 111ish mph, 60's in the 1.65-1.69 range. alt 2500 air about the same

So my question is whats limiting me..heads and Intake?

AdderMk2

considering how tiny those heads are. im gonna bet that you have a POS cam too

but yea, your h/i are jacked up

Corr1

I think the cam is pretty good comp cams 35-776-8, 304 in-316 exh. The heads could be the 190cc heads but I don't think so.

mjr46

what cam are you running???...heads are a little on the small side if they are 170cc, I run 185 heads and 750 carb and a custom cam with a ported air gap intake and I run low 11's at 120 mph on an easy launch.....so worked right and used with the right cam and heads the intake will work.

luckythirteen13

heads are way to small. i tried running afr 165 heads on a 331 and even with a sc it fell on its face at 4500rwhp. 185-190 is the smallest head id run on that motor. fwiw, i run 205cc heads on my 331. after you get some good heads, get a custom cam. then get a wider slick so you can launch the car at a higher rpm. if the car doesnt hook with a wider tire (after the heads cam upgrade) its time for more suspension work

Corr1

Is there anyway I can tell what cc heads I have without pulling them off? I can't find a part number on the outside of them anywhere. Now if for some reason I have the 190cc heads would a better intake help? The cam I have is listed a few posts back.

mjr46

on the front of the heads they should say if they are rpm heads or not??

Corr1

Ya they do but im sure that you could get the rpm's in 170 or 190cc.

mjr46

both the 1.90 and 2.02 equipped rpm heads are 170cc untuil you get up to the rpm xtreme's only do they change to 185's then from there the e-series are 205's

Corr1

Ok, that clears that up...thanks, Now if I go with 205's do I have to worry about piston / valve clearance? Or is that something that I should measure using the edel rpms first. Should I keep the air gap or turf it as well, I would rather buy a better intake then have to port it.