i have a 91 rs with a 3.1 i have owned mostly 2nd gens i had an 86 iroc but i'm not too sure what tranny i have in the 91! my ? is the v6 is shot and i want to transplant a 69' 350 in its place. i am fairly sure i have a 700r4 but i have heard that the tranny for the 3.1 will not fit a v8. only the 4.3 and other v8's can you all clarify this for me?

 

The bellhousing pattern is different between the 60* V6 and the V8 except 200-229-262 use the V8 pattern. Even if it bolted up the torque from a healthy V8 would soon kill it as it has less plates in the clutch packs.