not as much power after topend/exhaust upgrades
 

Hi there - thought id fire some questions..

Bought a 77 camaro 350/TH350 8-in-1 exhaust. Drove well, had a torker sp2 and eddie 1406. I got about 19mpg highway without OD cruising.

I put on 2 1/4 duals (no x over), vortec heads, lunati cam, popped in a otherwise stock 89 200-4r with stock stall, those aweful chinese professional products air gap intakes with a spreadbore to squarebore adapter and a 79 chevy qjet i rebuilt myself.. ontop of that i swapped the tiresome 2.73 out for a 3.42.. Of course there is a power diff, but not half as much as id expected..

I did check timing, was around 14 initial / manifold vac, and the most adv i got was around 28. I installed the crane lighter springs - experimented with various strengths etc.. i just dont think ive got the power out of her i "dreamed" of.. i did verify that the power piston was depressed on idle.. i then tried a stiffer springs and it also went all the way down so i have good idle vac..

my dizzy is good and weights in good shape.. I went 2 sizes up in jet/rod combo for my carb and set the qjet up pretty well - ie there arent any major problems (ie float, leaking, binding or flap limits).. i did notice a kind of stalling when i floor it - like the power drops off if im part throttle.. i kind of have to coax the power along with my foot if that makes sense.

I did install 2 different power piston springs as my cam has pretty good vac (not measured).. its a lunati barebones 280/290 from summit.. link: http://www.summitracing.com/parts/lu...01lk/overview/

pistons are 30 over and car DOESNT burn a drop of oil..

should i look @ my stock stall??

Im abroad at the mo and not at car - but when i get back i want to get her going much faster..


oops - forgot to say - i added long tube headers, looked about 1 5/8 with 20" 3" collectors fwiw..

the car drives good but man oh man it feels about 70hp down!

Re: not as much power after topend/exhaust upgrades
 

is the 2oo 4 r rebuilt ? if not it wont last long? d5 stock converter?

Re: not as much power after topend/exhaust upgrades
 

sorry for the delays, couldnt fin this thread! 200 is stock yes. I have ordered a vac tester and will map out my timing exactly. somewhere someone mentioned my cams ivc is 67 degrees and too late and that i should retard it by 4 degrees..

Re: not as much power after topend/exhaust upgrades
 

For the general lack of power, what static compression does it have now and before? And for your bog at part throttle maybe check your accelerator pump and see if that gives a good hard squirt when the secondaries open, there should have been a new one in the rebuild kit. Air valve can also cause bogs and it may need to be backed out a bit. I haven't looked at a qjet in about 30 years, though or longer, so i forgot most of how to tune them. Last thing - and I'm pretty sure you don't have a cat any longer, but those early pellet ones were pretty prone to clogging. Good luck getting it to go.