Anyone running a 350C?

[Geoff]

I am working on a 3.8 transplant into an 81 TTA, and I was wondering about the transmission that's in there. It is a 350C and has a lockup torque convertor. I'd like to save money where I can on this, and I like the driveability of the car with the lockup. I hope to get the car into the high 11's to start. Is it worth beefing this tranny up, or should I go a more conventional route? Also, can a GN ECM get this thing to lockup or will I have to do it manually? Any help would be appreciated.

Geoff

 

[Nordbert]

You should be able to use the TH350C with a N/A 3.8, but since
the TH350C uses a vacuum modulator, a boosted 3.8 will pose
a few problems that I am not experienced in dealing with. The
older TH350C's used a two conductor plug for the lockup. If you are going to replace the complete harness with a later
harness, you will have to replace the 4-prong plug in the case
with one from a later transmission. Your local transmission shop
should stock new ones.

 

[Geoff]

That's a good point about the modulator, I forgot all about that thing (hard to believe because it went out twice while I was driving the car). The thing is, it is in a turbo car - the TA has a turbo 301, so i guess I'll have to dig into the plumbing and see how GM did it. Thanks for the info.

 

[GNeric]

Just make sure the modulator doesn't receive boost and you should be ok. The modulator valve moves inward when the vacuum signal goes to 0 and returns outward to the modulator when vacuum is restored. It should still work ok as long as the diaphragm doesn't rupture.