From the pictues it looks like your block has new pistons in it. What is the purpose for the change? With 64 cc heads looks to me like your going to be close to 9.5 to 1 and use larger gasket if need be. Correct me if im wrong but arent the 4 valve flat pistons +5 cc right?
I would save the piston money and get aluminum heads. They will hold up and make good power. More importantly they are in the block and ready to go. Unless you want to run n2o i would leave them in place.
You can use a press to remove and install piston pins. They are cheap at harbor freight and always good to have around the shop. If not im sure at least one of your freinds has a press. If not machine shop should be very reasonable on this work.