[bren566]

I'm hoping to get back ito a Pontiac and have been looking at a 85 Trans Am with a 305 and computer controlled carb. At sometime in its life, somebody removed the catlytic converter,installed headers,3" dual exhaust, and edelbrock intake. For some reason they left the factory distributor and carb on it. What exactly does the computer control on this car? Can I throw in a hei distributor and a 4bbl carb and be done with the computer, or is there more to it? I've looked her over once, but are there any specific areas underneath to look for rust? Thanks!

[3tas4me]

The computerized engine controls back then were pretty basic compared to now. I would make mods that work with the computer system rather than try to defeat it. The ignition system in the car has a knock sensor that helps protect the engine. The electronic carb keeps the air/fuel mixture optimum in most driving conditions but has no bearing on full throttle. I would make sure your engine and all systems are operating at peak efficiency first, then do some mods. If you want to do away with the computerized controls, then i would also replace the 305 with a 350 or better yet, a PONTIAC 400.

[giddygoat]

I have a 85 Trans Am that I replaced the 305 with a 350, keeping the computer system, it has modified vortec heads and a little more potent cam. Est power around 400 hp. I did not change the idle jets, the computer seems to have that covered, I did need to change out the mains and the needles. It is alot of fun to drive, although the shifting and lockup work fine for normal driving it does have to be shifted manually to get the best performance out of it. May need a shift kit or maybe some adjustments to the stepdown cable, just have not had the time to play with that yet. Get and wire diagram of the engine section and you will see what is involved, as stated above there is a knock sensor and two temp sensors, one on the drivers side head is for the heat gauge in the dash, the other is on the thermostat housing, this feeds into the computer. Then theres the pressure sensor on the firewall and the carb enrichner and ignition system. I have been told that this system does not like it if it has a 180 thermostat, the 195 I believe is stock, maybe the cause of the anemic shifting as the computer may be thinking the engine is not fully warmed up, not sure....