what is the cam duration at 0.050"?
why shorty headers?
I would guess around 360hp and 450ftlbs.
A good build if you have a 3.08 gear. You could use up to 9:1 cr, a cam in the 212-218 degree range at 0.050", and would be better with long tube headers. This would be a 400hp/500ftlb 454.
If you have more gear, like a 3.73 gear, then you could use 9.5:1 cr, and a cam in the 230 degree range. This would make around 450hp.
what is your ignition timing setup? initial, total mechanical, and how much more from the vacuum advance?
BBC's eat cams. be careful not to use too much valve spring and use an oil additive. zddplus.com.