At 8.3 CR I estimate under 700 HP at 8 psi with BDS competition blower.

Using big valves, fully ported, (2.3/1.9) and 9.5 CR still under 750 HP.

And with 9.5 and 8 psi with roots blower you will be getting real close to detonation problems without an intercooler.

IMO you are gonna need Nitrous to get to 900 hp .................

I est just under 775 hp with the natural 10.25 CR 540 drag race max power configuration .............

Kitz