Engine SwapEverything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.
Welcome to ThirdGen.org!
Welcome to ThirdGen.org.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!
I currently have a 92 RS 305 TBI 5 speed car. I am wanting to swap over to a 700R4 with Dana's Shift Kit (I know thats blasphemy to some) . I am looking at picking up an 85 Trans Am w/ freshly rebuilt 305 TPI & 700R4, Posi rear and 4-wheel disc brakes. Guy doesnt have the title for the car and there is good bit of body damage so I can get the whole car for a song!
I am wanting to swap over the entire drivetrain with rear end. Am I going to have to do anything special to get my gauges to work? Am I correct in assuming that the donor Trans Am has a mechanical speedo and I have a VSS? Anything else I should know before taking this on?
The TA should have electronic speedometer, but your '92 will have a VSS buffer box, which the '85 won't have. The '92 will also have VATS, which the '85 doesn't. You'll have some things to work through, but nothing insurmountable.
Couldn't you take the tailhousing from the 1992 tranny and put it on the 1985 tranny and thus the speedo will remain indifferent?
If all else fails, I'd think soldering in the resistor for the VATS would solve that issue - then the no-start signal would never even get transmitted to the ECM (which wouldn't connect and/or understand it anyway). Maybe?
Would want to swap over the brake Proportioning valve for the rear disc brake setup.
New fuel pump for the TPI as opposed to TBI (I know TPI has higher pressure, but don't know if fuel pump is the same)?
I would think the rest is simple swap, plug, and play - with the wiring harness being the most difficult (in my world anyway, I hate wires)!
Couldn't you take the tailhousing from the 1992 tranny and put it on the 1985 tranny and thus the speedo will remain indifferent?
No. The '92 tranny is a T5, and the '85 tranny is a TH700.
Quote:
Originally Posted by camaronewbie
If all else fails, I'd think soldering in the resistor for the VATS would solve that issue - then the no-start signal would never even get transmitted to the ECM (which wouldn't connect and/or understand it anyway). Maybe?
No, VATS interfaces with the ECM, and the '85 ECM won't accommodate VATS. Better to just hardwire past the VATS.
Quote:
Originally Posted by camaronewbie
Would want to swap over the brake Proportioning valve for the rear disc brake setup.
That's a given.
Quote:
Originally Posted by camaronewbie
New fuel pump for the TPI as opposed to TBI (I know TPI has higher pressure, but don't know if fuel pump is the same)?
Stock they are different, but you could either put the '85 TPI pump in, or just drop the '92 tank and put in a replacement TPI pump.
Quote:
Originally Posted by camaronewbie
I would think the rest is simple swap, plug, and play - with the wiring harness being the most difficult (in my world anyway, I hate wires)!
The wiring differences would be the most difficult part.
ill be moving to southern cali in like a month what yea say??
Cali? I live in Houston, lol
Thanks you guys for all the responses!
Is there a posibility of using the ECM off of a newer TPI setup and physically getting rid of the Cold Start injector? Am I correct in assuming that the 85 TA has a MAF setup and I would need the computer from a newer MAF TPI car?
I would like to keep VATS if at all possible.
Again, thank you, I appreciate yall's time and help!
) . I am looking at picking up an 85 Trans Am w/ freshly rebuilt 305 TPI & 700R4, Posi rear and 4-wheel disc brakes. Guy doesnt have the title for the car and there is good bit of body damage so I can get the whole car for a song!
I missed the 5 speed vs. auto. 
