I've seen turbos on the 76 and newer style of motors, but never on an old style, that should be interesting.
As for a rebuild kit that might be tough. The early style motor is getting very hard to find parts for these days.
http://www.rockauto.com shows a full gasket kit, but you would need to add rings, pistons, main & rod bearings, probably a few other items. Rockauto seems to have most of it, but I don't see pistons listed.
Seems like I've seen a full rebuild kit and a re-ring kit in the JCWhitney catalog but I can't find it looking through
http://www.jcwhitney.com Their website isn't the easiest to find anything on though. You might also check with
FelPro/Sealed Power (click them for link) and look through their catalog. If anyone makes a full kit it would them, and that would give you a part number to hit up your parts dealers with.