With any engine, head flow is everything. Good porting will enhance ANYTHING you do to the engine, now, and in the future. Greg Gessler is among the best head porters in the Northeast. He did the heads on my 70 GS455.
http://www.gesslerheadporting.com/gesslerheadporting/ghp.nsf/822dcaaaa26c6da985256dd80023623d/e8e174c35393295085256e5e000a5cde!OpenDocument
I'm not sure how anyone could predict the amount of power you can make, but good porting will up the amount of HP the heads will support. Forced Induction is a great equalizer, and you do not need a big cam. I would go with a super charger cam if you plan on running the supercharger. The engine tune will be everything. You cannot run the same amount of boost with higher compression. Prevent it from detonating, and give it enough fuel, and it should be fine.
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98 Riviera SC3800 All stock except gutted air box.
1970 Buick GS455 Stage1, TSP built 470BBB, 602HP/589TQ
Best MPH, 116.06 MPH, Best ET, 11.54
https://www.youtube.com/watch?v=UHCda-t_Jls
https://www.youtube.com/watch?v=sfT2tEO4XcU