getting ready to swap 700r4s

what would i need to change the 27 spline tranny to the 30 spline 700r4? My 84 caprice is starting to kill the 2-3 shift and the shifts can sometimes be eradic. super street fighter tranny, (Rated up to 600 Ft.-Lbs!,)is one click away from being ordered. also, does this seafoam stuff work? I have a bad lifter tick and it says on the bottle it removes lifter tick. Im pretty sure the cam lobe isn't worn because it will do it only very occasionally for a day or two but its not going away. any response is greatly appreciated. thank you.

Just get a transmission and torque converter from 1985 or newer for 30-spline. It's the input shaft.

All of them have the same tailshaft yoke size and spline count, which is interchangeable with the TH350 and older transmissions.

so i can swap the trannies with no problem?

so i can swap the trannies with no problem?

As long as you use the proper torque converter, yes - no problem. A 27-spline converter will not physically fit a 30-spline input shaft, while the 30 TC will go over a 27-input, but you get no drive and a whole hell of a lot of noise, plus a damaged torque converter and input shaft.

oohhh! ok i totally forgot the auto trans bolts to the flywheel instead of like a manual trans.