Has anyone had an Indy Maxx Aluminum block machined from 400 Mains to RB Mains? The limited crank and bearing offerings for B mains has me thinking I might need to bite the bullet and open the mains to RB size. Is it just a matter of line boring the housings? The bearing tang reliefs look like they're plenty deep in the block and the caps. Anything need to be done with the rear main seal? B and RB take the same seal, right?