Hey guys!

Well for all yalls who think the little 305 is a POS (24 hours ago that included me) Check this out!

Before: STOCK 1985 Trans Am w/305 and Q-Jet-155hp factory rating. When I first got it it would lay over at 4,000 but after some air box mods I got it to "pull" to 5,000. But to give you an idea of speed, it got beat by a Chevy HHR...loaded with chicks...yeah, I wanted to die.

But then....

Edylbrock 1406 Carb 600cfm progressive mech secondary.
1" Carb spacer/ Q-Jet to squarebore
Hooker 2460 coated headers

After: CANT CONTROL THE TIRE SPIN! It is absolutly BAD! No exhaust just the headers. Sounds like a drag car. And is faster than my GTA! I know b/c my buddy was flying interference in my car...AND I SMOKED HIM! This little 305 has got to be a low 15 second car (at 8000ft density)

Now I cant wait til the new cam comes in. Im going to go to a .420/204 I - .442/214 E Summit cam. And then a Edylbrock performer EPS manifold. Should be fun...and to think im selling it lol.

 

Your not using your stoc Q-Jet anymore? And what is your timing set at?

Nice to see a 305 do well without alot of money in parts

 

The Performer carb isn't mechanical secondary. The throttle blades are opened mechanically, but air flow is controlled by a demand-sensitive air valve above the throttle blades. Basically same concept as the q-jet, although controlled by a weight instead of a tension spring.

What distributor are you using now?

 

Its the stock HEI that I ran up to 15 initial. This car is really amazing, its just as cheap as can be ya know. Oh BTW the Cam is on its way . Now the hard part is getting it to the strip without getting busted by smokey lol, may have to tow it.

 

Stock HEI isn't a very good partner with a Performer carb (or any non-computer carb). 15 initial isn't going to be enough. If you have access to a dial-back timing light, set the timing at around 36 at 3000 RPMs or so (or whatever RPMs it isn't advancing anymore). It'll probably kick back in the starter because you'll have so much initial timing, but that's how it will run best.

 

You've disconnected the TPS with the stock carb and the ecm relies on the TPS signal to advance the timing. You can check this by connecting your timing light and running the rpm's up while watching it. It will likely stay pretty steady.

If you've still got the VAC sensor hooked up you may see some variance, but with TPS unhooked the ECM is stuck thinking the carb is at idle/low throttle.


'course who knows whether the stock dist is still in there after all these years.

Oh and imagine how cheaper it would have been if you were using the stock q-jet with properly functioning computer controls. Better performance, mileage and no icky edlebrock carb sitting on top of the motor, but I understand you're getting the summit cam. I hear it's matched to your carb.

 

Agreed with above- as soon as you ditch the computer controlled carb you should also replace the computer controlled HEI with a non-computer controlled one. You'll like the change.

The exhaust system on the LG4 is one of the worst in stock form. No doubt headers wake them right up, but the stock manifolds are far from the only restriction point. Make sure it's at least a 2-1/2" (preferrably 3") exhaust all the way back, too. Some "emissions legal" headers have a y-pipe that necks way down to fit the stock 2-1/4" LG4 cat and that's just rediculous- the restriction just moves further downstream to the cat, intermediate pipe and muffler.

BTW- you'll like the cam change, too. The stock LG4 cam is what you'll hear referred to around here as the "peanut cam" with 179/194* duration. VERY small. The 204/214* cam you are buying may be mild by performance standard, but it's a real fire-breather compared to what you got in there now! Your 1985 LG4 fortunately uses higher compression flattop pistons (9.5:1 compression) so it can swallow a performance cam better than the low-compression (8.5:1) LG4s in earlier year Camaros. 1985 was the first year for the higher compression LG4 in the Camaro.