...In My Opinion, You should have gone with the TRW Flat-Top Pistons. With a 10.5 CR*, proper carb and Manifold you'd be Pushing 'near' 450 HP, at the Flywheel. The Cam and Headers, look correct for it.
* a 10.5-10.6 Compression Ratio would depend on the Cyl. Head Chamber Volume...All other factors being the same. Replacing the Dished Pistons and keeping the CLOSED Chambers, Really Wakes these Engines Up. Just be sure to us the Highest Octane 'Pump' Fuel, you can find. Has Never been a Problem with my cleveland at 63cc Cambers, .588 lift cam (int and Ex) at a 292 Duration on both. Also, had the bowls Polished, Ports Untouched, Huge Valves. When I ran dual quads, the HP was at 520. Torque 490.
Now, I run a Dual Plane 'Air-Gap' with a Holley 750 Vac/Sec (for the Street), Data Input were at the Minimalist Values, processed on a 'Desktop Dyno' Program. 480HP/450Torq. If I were 'Racing', I would go with a 'Double Pumper' Mech-Secs...Or FI. All figures are + or - 5%. FWIW
MJ