If you want to make full use of your GT35, then you'll be wanting it to rev to 8500, which will mean different valve-train, rods and crank .

Alternatively you could go for a more budget orientated engine and be happy with 600 bhp...

Good head , solid lifters (as the GT35 will be wanting to live at 8k ) and standard (but perfect condition) rods and crank and genuine Cosworth LOW COMP pistons.