My rebuilt small block chevy has blue smoke on start up,runs fine.?

I agree with the above. Valve Guide seals. I'd think that if the rings werent seating, you'd get a lot of blow-by and the smoke wouldnt go away.

As for posting Chevy Small Block question on a Mopar A-bodies site. Here's the forum for you.
Chevy's A-Body Site -> http://www.chevelles.com/