Silly Head Question

The chamber size only determines compression ratio. 62 is VERY close to the factory (factory stats ranged from 62-66cc's depending on where you get your info). So your compression ratio shouldn't be altered much. Taht being said, you should e fine adding forced induction to it. As for swapping heads... I wouldn't. The GT40X are OK, and forced induction can make up for some of their downfalls. Velocity still matters in a forced induction motor, just not to the degree that a NA car does. Stick with what you have and take the money you would have spent and put it back for a new block, because even with those heads and a mild turbo setup, you can make block splitting power pretty easily. Good luck!