Originally Posted by JLBpontiac350
so im trying to buy a th200 tranny for my 85 grand prix with a chevy 305. but all the places i call have th200's for differant years and differant cars....are all th200's interchangable? am i doomed to never find one specific to my car?
Do you really mean the TH200 3 speed automatic (some were lock up, aka "TH200C
"), or do you mean the TH2004R automatic w/overdrive?
If you now have the TH200, it's a relatively weak tranny, I'd swap it out for a TH350 if your engine has been modified for more power- or at least build it to handle the engine.
The main thing to be aware of is the bolt pattern of the bellhousing- there are different patterns for the Chevy and the other GM's (aka "BOP" for Buick, Olds, Pontiac. This includes the RWD Caddy's as well). The TH2004R can be had w/a "dual pattern" bellhousing that will mount up to either.
Dual Pattern TH2004R
More on ID'ing what tranny you have HERE