Oh & to fully answer your Q Mike as to why Kent even did an Xr1... The original design was purely to do an XR2 P7 block, & @ the time they were started on this deal, MP was out of R3's (they had no blocks avail for over a 2 year period) They were switching vendors out of Cummins for their machining, Chrysler was looking bad financially & very well could have never seen another R3. So he decided to modify things & be able to do his own 59 & 48 blocks to fill hole of missing R3 blocks in the Market.. then by time he gets his stuff about done MP gets new vendor to machine the R3's & is keeping them back in stock routinely. But eventually... MP will cease to exist someday, whether that's this year or 10 years from now... & will be good that these private aftermarket blocks exist. Overall I think the R3 is a better piece, but I'm glad we have a backup plan if Chrysler goes belly up tomorrow.