help decoding trans and rebuild

Trying to figure out if my trans is a lockup trans or not. The numbers of the rail are PK 3681053 4083 1473. Person rebuilding my trans said I need to find a 727 from a big block as a donor to use some of the internals to rebuild mine if its indeed a lockup trans. Its behind a 350hp 340. Also if you guys have any helpfull advice about rebuilding this trans please tell me. I know enough to remove it and reinstall it and thats it. Car will be used for cruising, car shows, smokey burnouts and the occasional stop light hole-shot.


thanks!