R6 440 block?

The "R" race blocks I believe were the older direct conection/mopar performance non-production
small blocks that had the lifter angle changed to 48deg. To better line up with the push rods like the
B-RB stock blocks. Better to stablize the valve train at higher rpm. They were 340 bore blocks.
I think the lifter bank angle stock was something like 53 deg.
They were in the old parts books and mentioned in the 80's engine bible's.
Rick