Well, we could get into a Callies crank, Carillo rods, etc., etc., but anyone able to afford some of that stuff would have an engine builder buyin' the parts. So, let's keep it to where anyone reading here could build the motor just by missing 10-12 months worth of house payments.

Speed-O-Motive has an affordable 435 kit featuring steel crank and rods and forged pistons.

Your job is to contact them via email and ask the rpm limit of the reciprocating assembly that is furnished with the 435 kit. Also ask if we should be using a stock or an aftermarket block to start with. Report back here.