RJ Dietrich

hi guys. my dad has an 86 or 87 sport coupe that had the 4bbl 305 in it. we already have the motor and trans out because it is being swapped to a carbed 350sbc. we just want the simple set up with no electrical crap. how ever, my dad would like to run the original gauges and ignition in the car, therefore we can not completely ditch the oem engine harness.

i did a 350 swap in my old 86 iroc z28 from a 305tpi and i can not remember for the life of me what wires we still had to use for the HEI dizzy, and to keep the turn key ignition working. any help would be appreciated.

he mainly wants:

Speedo (which im pretty sure it just runs off the trans)
tach
temp
and voltage (i may have talked him into going with aftermarket gauge, but info would be great in case he changes his mind!)
ignition key

pics of how you guys did it would be helpful

thanks guys

RJ Dietrich

also, i have been trying to search around for a possible harness thats basically just plug and play with only the couple of plugs we need. if anyone knows of any, please drop a link below!!! thanks!

JoeMonte

I am doing the same swap here fairly soon in my '85 Trans Am. I don't plan on using any of the original computer wiring for my distributor or carb, so those will both be replaced. How do I go about wiring up the switched ignition or is that just a mechanical switch? Thanks for any input.

five7kid

iTrader: (14)

Not sure what you're going to do for ignition with no "electrical crap". Light a match each combustion cycle?

Sorry for the snark, but I get weary of the unjustified disparaging of electronics crap. Unless your 350 is an all-out race engine, that computer controlled carb that was on the car is the best street/performance system available. Too bad you aren't willing to open your eyes to the truth.

But, all that aside, to your questions.

Which wire to use for the HEI depends upon whether it's an '86 or '87. If '86, it's the same connector. If '87, it's the pink wire on the coil for the power, white wire for the tach.

Other than that, you hook up everything like it was originally. The harnesses for the ignition and gauges are separate from the ECM harness, so just remove the ECM harness (and you don't need to cut anything to remove the ECM harness).

RJ Dietrich

Thanks for the info. This is all my dads idea. Im a ford guy myself. Ive never really messed with older carbed stuff. All fuel injection. He decided to do the swap because the 305 blew up, but doesnt want any of the computer controlled stuff. Wants old school style.

midias

Computer controlled carbs are old school and will run a normal 350 better than any edelbrock or holley. Other than that the gauges just run off the sensors so make sure you put them back in the motor. Also make sure you get a normal vac advance distributor. The computer controlled one wont work.

naf

iTrader: (7)

if an 87 the in-tank pump is also powered through the ecm harness. running without it can cause a massive restriction that the block mounted pump may not be able to overcome. there's also torque converter lock up to consider if automatic.

other than that the ECM harness can be removed in its entirety through the passenger side fender well leaving the engine harness complete to run the motor and feed the gauges.