Need a new rear seal and want to id block be for I start. Got the motor from a wrecker, said it was a 80 or 81. Is there any way of telling the years apart. Thanks

All the rear seals should be the same, 1960-86 Slant Six
Look for the ID number stamped into the top of the block, that will tell use what year the engine was assembled.
DD

There is a listing for two seals one for 80 and down and one for 81 to 86 two diffrent part numbers

Donno whose catalogue you're looking in. There's a different whole-engine gasket set for '60-'80 vs. '81-up, because the head gasket's different, but the rear main seal is the same.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

http://i7.photobucket.com/albums/y281/lauchlin/part.jpg