i tried asking before but no response.... im swapping into my car a 350 that is out of a late 70s car.... i have heard people say that some motors have 2 peice main seals, when i replace the seal i get the one that is correct for the motor, right?? and also is there any other bolt up issues i will run into?

 

Yes it will be 2 piece rear seal. Get that seal. The problem bolting it up is it will require a 2 piece rear seal flexplate/flywheel.

 

which flywheel do i use the 350 one or the 305 one??

 

Use a flexplate/flywheel intended for an '82-85 3rd gen. It will have the proper bolt pattern, and will fit within the bellhousing. Since your car is an '84, you should be able to reuse your current piece, assuming it's in good condition.

 

are they a different tooth pattern?