Since we (mostly) build replicas here then maybe look at a modern day interpretation of a Boss 302.
You can get the block from Ford Racing and I notice that CHI is making a manifolds for their 3V clevo heads to fit 8.2in motors.
http://www.chiheads.com/ (-just incase)
Lots of quality parts are readily available to cope with your 8000rpm - the hardest part is going to be finding someone with enough experience to know how to make it last at that level and that you trust to put it together. (and the $$)
I dont think you'll have to worry about the HP
Good luck & Let us know how you go with your project.
LoBelly