Tranny-Engine Seal '77

looking into buying a '77 for a project car. the owner said that the seal betweenthe engine and tranny is broken, and i was wondering how much the parts would be. 

There isnt a seal between the engine and trans there is a rear main seal in the engine and a seal were the torque convertor goes in the trans. Both are a pain to change the trans requires the engine and trans to be split the rear main can sometimes be changed without pulling the engine but there are no garanties.

Thanks for the help, even if it wasn't the answer I was hoping for.

Guess I have my work cut out for me.