Hey I'm far from internet suavy and I tried a search on what I was looking for, and I'm sure with all the information on the site I could find it. I just don't know what to use in the search.

I'm in the middle of an LT1 swap into my '86 IROC and I'm just about to the wiring portion and wanted to know if I needed the 3rd gen wiring harness at all (I'm assuming I probably do). I'm asking because I have someone interested in taking my old 305 TPI/700R4 off my hands.
Also i know it's not the place for it but what's a fair price for the tpi/700r4 (~93,000 runs good, but uses about a quart of oil between oil changes) and if I do need the harness how much should i take off the price of the motor/tranny?

Sorry for the post as I'm in a bit of a hurry, I promise I'll try to teach myself to search better in the future

 

Yes you need a good portion of your existing harness for your LT1 swap, however if you could get your hands on the harness from a carb'd car of the same year you'd pretty much be just as well off.

As far as pricing, your tpi setup itself without a harness is probably worth about 200-300 or so, the 305 longblock $50 roughly, and maybe 175 for the trans.

 

That's about what I was thinking. . . Thanks very much for the speedy response

 

However, if you can find a 4th gen LT1 car wrecked that you can get the underhood fuseblock, you don't need any of the engine harness at all, just the C100 bulkhead connector which isn't tied into the TPI harness.

 

It may not be tied to it per say, but all of it is "tied" together, there is no parting line, wires come from both the ecm connectors and the C100 and 207 and go to the same components, it doesnt just seperate.

 

Mine did, two seperate harnesses. But could be the difference between a V6 MPFI and TPI harness. I actually had a plug on the driver side where the oil/temp/ac plugged into the C100 harness wiring because this is where I spliced in my oil/temp/ac at.

 

On a V8 harness they go directly to their components. Aside from that fact you've also got quite a few that go down in through the C207 that most like to use, though I guess not having a speedometer, aldl port, or using existing ecm fuses to power the pcm is always an option...

 

I'm using a dash harness from an 87 GTA and that's it, I'm using the wires that go from the ECM fuse to power the PCM and the injector fuses to power the injectors and ignition in the underhood fusebox, plus the fan fuse to power the fans in the underhood fuse box (using 4th gen fans) and wired my speedo up from the VSS output from the LT1 pcm to the wire that goes to the speedo since the speedo is a 4000 ppm unit.

 

Can anyone explain the steps inorder to swap in the LT1? Would the motor bolt up to my existing 700r4?