Most likely a B/RB. 650 horespower doesn't really have a low cost option. Lol. Or not one that will live very long!
You can build an Indy head stroker for under 10K that will last forever if you do your own assembly carefully. It can be done with a flat tappet cam but a roller would make the 650 number easier and possibly live longer. The roller would probably bump the price over 10K for the package to support the roller.
You don't really need external oiling with the correct rod and crank choice so that would save a bunch of dough.
Gus
