347,
I only mentioned pulling the heads if you wanted to go to a bigger cam. You would need new (stiffer) valve springs or if you wanted a roller cam the heads need to be removed to get the lifters in.
Block mods would be things like a main cap support (girdle), studs, or aftermarket main caps, etc.
For the rpm you intend to run (7000 to 7500) the cam you have should work fine. A cam with 252 to 255 deg intake/exh with about .575" to .590" lift on a 108 to 110 lobe center installed at 104 to 106 deg would really make it a top end screamer without sacrificing too much low and midreange power. It would effect daily driving type usablity though. I would try the manifold and carb first then decide if you still want more go go. The Victor Jr or the newer Performer RPM air-gap that mkcobra mentioned would work well. I recently installed a RPM air-gap on a 351w and it ran like gangbusters. Great manifold.
Good luck with your project,
--Mike
PS or, you could do this!
