So, I'm going to eventually be putting a newly built engine into my Trans Am(1986, A4, carbed, 5.0L originally). I have decided that I am going to ditch the ECM controlled carburetor and distributor. The OEM Q-jet was leaking fuel when I took it off, as the fuel inlet was stripped a long time ago and jerry-rigged when someone tightened it in crooked. So I don't think it's salvageable even if I wanted to.

I figure it's easier to just ditch that ECM controlled stuff, and go with aftermarket carb and dizzy. I have a small block four bolt Chevy 350 that I will be building, and will go with some aftermarket aluminum heads anyway. Going to try and get 300-350 RWHP out of it so it will be pretty far from stock. I imagine that's quite an extensive tuning job. From what I know about GTO mods and computer tuning, anyways.

I've got a 700R4 trans that will need to be rebuilt as well, and a 3.42 rear end off a 4th gen already in place. With that will be a new TC, depending on the cam that goes into the motor. Obviously the trans will need work regardless, as the gear and tire sizes are nowhere near stock, so the speedo will be WAY off.

I am aware of the fact that I lose TC lockup when the ECM stops handling the dizzy and carb. I should still go for a locking TC if I want to preserve any semblance of decent highway gas mileage though, right? I'm no transmission guru, so bear with me. Does the 700R4 only lock the TC in 4th gear, or will it lock in any gears? Is the TCI vacuum switched lockup kit sufficient if I want to keep a locking TC? I understand that the ECM's only interaction with the transmission is the TC lockup. Is that correct?

The distributor and carb swap won't affect the electric fan control, speedometer, tach, oil pressure, or temperature reading, correct? As long as those sensors are replaced on the new engine and the connections are made, I still keep that functionality?

Sorry for any questions that may have been answered previously, but I've been reading for several days straight now and searching like a mad man, and just want to make sure of some things before I really commit to this build. Also, would be nice to hear some pros/cons of ditching the CCC and dizzy.

I was personally not a fan of the ECM controlled carb/dizzy when the car was together and stock. Had nothing but problems trying to get the car to run properly(too rich, too lean, knocking, etc), even after swapping multiple sensors out. Hell, for all I know, my ECM might have been bad. But I have a 2006 GTO to fulfill any needs I may have as far as computer controlled tuning is concerned, so I'm going old school with this one.

I am also going to do the large majority of the work myself, with a friend of mine. It's just more fun to learn all the things you want to do, and then do them yourself, for a project car.

P.S. I hate these stupid f-body spare tire wells..... Only place on the car that has rusted through(as of now, that is).

 

Correct

https://www.thirdgen.org/forums/tran...-computer.html