Anyone know what tranny came stock in a 1981 C10 with a 6? I have an opportunity to pick one up super-cheap (the 81 c10, that is), and was thinking I might throw one of my 350's in it and just chuck the 6. The 6 needs a head gasket. I figure if I have to work on it, I'll just drop a 350 in it instead, as long as the bellhousing matches and it's not some cheesy little car tranny that'll break behind a sbc... BTW, both the motor and tranny in this truck are under 20k miles since rebuild. So can I do it fairly painlessly?