i have a auto 86 trans am (stock 305 tpi) i bought the car with rod knock and am peicing together a lt1 swap which i will be doing in 2 weeks. i have my old motor pulled and a lt1 harness and ecu ready to go in. very new f bodies and i have a few questions. my car is an auto and the motor harness and ecu are out of a 6 speed lt1. i plan on bolting up the 600r4 from my tpi. the only differnce i have seen with wiring diagrams are lock up clutch for the torque converter. is there a way to hook it up? will i encounter any other problems? i have read the stock (lt1) headers do not fit but if i bolt my stock exhaust manifold (305tpi) to the lt1 i will have no issues with clearance. my tpi car has a single o2 sensor and the lt1 has 2. is there a cheaper easier way than getting another 02 and welding a bung onto the exhaust for it? also, how important is the 4th gen fuse pannel/ relay box. according to all the info i have its only 2 wires going to it. couldnt i just splice them into my current tpi stuff?

LT1 with 700R4---
You need these:
1. 93 throttle body but you may have to swap IAC's on it
2. 93 throttle bracket
3. 93 TV cable
4. 95 4L60E VSS
5. 95 4L60E Reluctor pressed on the output shaft
6. TCI vacuum switch to control torque converter or lock up, dont remember which one but needed
7. Vacuum lines and maybe an additional relay for the TCI vacuum switch(depends on how you wire it)
8. A tune with Tranny trouble codes turned off
maybe? - 9. Maybe 4L60e rear housing
new product - 10. TCI TV cable eliminator kit(This would eliminate 1, 2, and 3 from above)


Exhaust -
I dont think stock exhaust manifolds from TPI will clear the large d-ports on the LT1 heads. I could be wrong though. Everyone seems to recommend 1 5/8" or 1 3/4" thirdgen headers. With shorty headers you would not have any problems with ground clearance. An O2 bung is easy to do or have done, cut a 5/8" hole in the pipe, insert bung, weld around bung.

Wiring and Fuse boxes-
The 4th gen fuse panel and relay box and somewhat important. I used them both when I first got my car going but no longer have either. If you have them, I recommend getting the car to work with them first. Then after everything works go through and "trim" down the harness. "Trim" means cut out all the wires you know for sure you don't need and combine wires. Shbox.com should have most of the 4th gen wiring you need and the Tech Articles at thirdgen.org has thirdgen wiring diagrams somewhere. And no, can't use TPI computer or engine harness.

Hope that helps a little bit.

i thought i was told the 80's tpi throttle bodies were the same as the lt1. i have all the old tpi throttle body stuff. im getting a lt1 that had a 6 speed so it will not have the tv cable.

also the vehicle speed sensor on my 700r4 is electric i cannot just wire it to the lt1 harness? (i know they are both 2 wire and might even have the same plug but im not 100%).

as for the torque converter clutch did my car have the tci vaccum controll (what is it?) or is it somthing i have to get off another car?

700R-4 VSS's have been done 3 different ways. In the early days of VSS, the VSS was part of the cable driven speedo. Thus, the VSS was in the dash. The second design still used speedometer gears, but the driven gear and carrier had the vSS built in, and no more cable. The third design has a reluctor ring on the transmission output shaft where the plastic gear used to live, and there is no driven gear. Just the sensor. This was done on the 700R-4, the 4L60E and the T56. Being as this signal is all your computer is looking for from the trans, and being that a 700R-4 can provide it, as described above, there's no need for any pressing, unless it proves either cheapest or easiest. Probably easier to change the entire output shaft, or entire transmission. The '86 700R-4 isn't one of the "good" years of 700, and uses the first-design VSS.

im not sure if i miss understood but my 700 that i pulled out of my car has no cable its has a 2 wire sensor plugged to the tail shaft first design you mentioned uses a cable

did yours have the digital dash? Those used the second design.

Will the LT1 exhaust manifolds fit in a 3rd gen w/ an LT1? If so, that is an option.