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Need some help from the group here. I'm swapping out the 700r4 from my 88 Firebird with a TH350. I was under the impression it would be a pretty straight swap, but the TH350 is definitely shorter (To the tune of about an inch and a half, give or take). Worse yet, the tailhousing on the TH350 does not have the bolts necessary to attach my torque arm bar, But the tailhousing from the 700r4 is entirely too long. What am I missing guys? Thanks for your time. See attached pics. First row is from the 700r4, 2nd row is from the TH350. 700r4 700r4 700r4 700r4 700r4
I'm no parts expert here so bear with me on this. I have this swap in my 84, and was able to retain the stock drive shaft and transmission cross member from the 700r4. I believe what you need is a long shaft th350 (this is what I am unsure of....I can't tell you tail shaft lengths so I might be leading you slightly astray here...). You need to take the tail shaft housing from the 700r4 and also use a tail shaft housing spacer/ adapter to make up the difference in tail shaft housing from the shorter 700r4 to the long th350. Unfortunately this causes serious incompatibility issues with the speedo drive and I ended up putting an aem x series gps speedo in the car. Other than that it all bolts up and seems to work fine without any need for fabricating parts. I'll look into the spacer a bit more, I have no idea where I found mine.
