Ok small question. Ive got a good 700r4 out of an 89 Blazer. Just wanted to check if the 91 firebird had the same spline count. I know the Blazer has the 30 spline and wasnt sure about the bird.

 

the 700R-4 changed from 27 spline input, for the V8 versions anyway, to 30 spline in late 84, and stayed 30 spline forever after.

 

I think you will still have to swap the tail housing though.

 

Hold up. This shouldn't matter. The Blazer trans should include a torque converter. If your trans failed, then even if you have a $1000 aftermarket converter on it, you can't put your old converter on a good trans. The converter will be full of all kinds of debris. Even if this doesn't kill the converter, the debris will get into the blazer trans and hurt it. If you do have a converter you love, flushing isn't good enough. send it in to be cut open, cleaned, and re-welded and re-balanced. It's cheap insurance.

 

Im putting the trans from the blazer with the blazer engine inside the firebird. The trans is fine just having it rebuilt before i get it in there. I have a 700r4 tailhousing to put on this 700r4. The only thing i was worried about was that they were both going to be 30 spline.