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!

 

One other silly question; Does the 305 vin H carb engine use a mechanical or electric fuel pump?

 

mechanical fuel pump WITH a return line to the tank

the computer controls the mixture ratio for the primaries only. it also controls the timing advance with knock sensor feedback (and EGR/AIR function, torque converter lockup and it has some control over the idle speed bump solenoid). the secondaries are purely mechanical and there's absolutely no reason to swap to a mechanical qjet or most other carbs.

it is a very good system when operating properly and can adapt to all but the more radical mods. the bottleneck for that system is the exhaust, cam and air intake (along with the rear gears and converter stall).

peruse: https://www.thirdgen.org/forums/carb...tions-lg4.html

the down side is the age of the parts/pieces and availability of quality replacements. but if you like to get dirty now and again, i'd recommend it. closest to fuel injection you can get and you get to enjoy the sound of the secondaries opening.

pull the carpet back near the driver/pass footwells and in back under the rear seats. If t-tops, inspect the areas behind the weatherstripping with the tops off carefully. battery tray is almost always toast but other models had the batt on the left side so used replacements can be found. make sure the gfx are in good shape, they're getting harder to find.