LT is apart, have a Question

Hey guys,
A couple of weeks ago I fired up the Lt for tyler, It was really hard to start, once we got it running and warmed up it started making a funny noise and had a loss of power, so we shut it down. now that its a little warmer we decided to tear it down. We found out it blew a head gasket, no problem. The thing is, before i mentioned it sounded like it had alot of piston slap when it was running. Well, the piston is in great shape and the cylinder still has cross hatching. Would the slapping noise have been caused from the weak gasket or should we pop a new piston in it.
And LT80, this was your motor build, your name is engraved on the head. :D
Also, when you shaved the head should the surface be really rough, we were just wondering if the head gasket would have a hard time seating to the roughness of it.
Thanks and sorry for the long post.
Heres a blurry pic of TY hitting a small bump in the lawn, somebody was messin with my camera again:grr:

Measuring the exact clearance of the piston/cylinder will tell you if it needs a new piston. .007 would be the point of replacement IMO.
The head should be fine. I think the slight roughness helps seal it IMO. :)