Agreed with LATECH. You would HATE that cam. As an engine builder and been onvolved in thousands of "projects" over the years, many times, one's "eyes" are "bigger" than their stomach. Rumpy-rump engines SOUND cool, but are a pain to operate.
A Bonneville is a classy "dark sider". That's what Pontiac people use to refer to the "big" cars. it is a TANK compared to the Pontiac "performance" cars of the era (GTO, Catalina, "2+2", Ventura). The Bonny has a longer wheelbase than Catalina. A nice "cruiser" is the best thing to do with the Bonny, IMO.
If you're REALLY interested in pumping up the Poncho, get Jim Hand's "How to Build Max-performance Pontiac V8s" published by SA Designs. Get educated on the strengths and weaknesses of the Pontiac.
The 400 block is physically stronger than the 455 block. The "stroker" kits make a much ore effective engine than a "built" 455. Cylinder head casting numbers are among the most imnportant pieces of information you can provide. Compression is controlled by the chamber volume in a Pontiac, not the piston configuration.