Guess the race part

That’s an excellent question. All the high rpm SBM custom cranks ive seen use a 2 inch rod journal. I’ve read somewhere that the Honda sized rod journals are too small for the reciprocating mass for anything less than a billet crank. But I have seen some that use a small block Ford main journal with the 2 inch diameter rod journal. I do know the factory oil system needs a lot of help once you start revving past 7500 rpm.