My 89iroc w/350tpi has some cut up areas in it.One place is the radiator fans.One must have been wired in direct,cause when the key is on the drivers side one runs.Plus mices chewed up the wires that go to the maf sencer.I've spiced it together while I'm working on bigger things.Eventually I want the engine bay back to a clean stock set up.The smog pump was removed and I think the alarm system may have been disabled.The stering wheel dosn't have the horn hooked up at all now.I'm wanting to know if a 305 wireing harness from the same year would have all the same leads on them or dose it have to be an 89 iroc 350tpi w/air and so on? Any coments on fixes to my list of problems would be apresheated.

 

A TPI is a TPI ; regardless of engine size
Obviously a TBI harness will be different

 

just checking,how about the year model? Say,86-89 go together and 90-92?

 

90 - 92 ( SD ) requires a different computer and some other changes

 

Breakdown for TPIs

85 is it's own deal
86-87 are similar and use a 165 ECM. A few changes and they'll interchange directly
88's are similar to 86-87 but a few more differences that Id put them in their own group. Also 165 ECM
89's are different from all other years. Quite a few mods to put them in something else. 165 ECM again. Closest pinout to 90-92 cars of any other year. Easiest year for a SD swap
90-92 are identical, 730 ECM

For TPI harnesses, there is no difference between 305 to 350. The long block, injectors and PROM changed. Everything else stayed the same

 

what dose SD stand for?

 

Speed density aka the 90-92 TPIs