nice truck! i was in the same boat, 55k miles original motor not much power. mine leaked oil like crazy. i ended up putting vortec heads on it and changing all the gaskets, new cam, timing gear.......lots of little stuff. runs great now.
might have been a good idea to do something with the pistons, but ill get a few more miles then rebuild the bottom.
http://67-72chevytrucks.com/vboard/s...ighlight=heads