Yeah, Ole is right. The hemi head is a very good head. If anything I'd get that hemi head ported or at least have the sharp edges rounded off inside the intake and exhaust ports. If you want to know the true difference the right head can make, the latest episode of Engine Masters shows it. They had an engine wit ha massive camshaft but a small head and it couldn't breath. They ported the head well and gained 92 hp. It's about the carburetor and the head. The camshaft only complements what the carburetor and camshaft are doing. If someone is making a pop top piston for a hemi, you just solved all your compression problems.
[video=youtube;aijyLKCvbU8]https://www.youtube.com/watch?v=aijyLKCvbU8[/video]