My bad, I should have been more specific and was asking about the cam bearing journal diameter. The 48 degree lobe does make a difference as well, obviously. Maybe the R blocks are all the same but it was my impression the later blocks and the Ritter's had an option for larger diameter cams. Carry on...
No the early 48° blocks did have the same journals as a 340 but the lobes are different when they moved onto the R2 in our three they made them all the same size so they can get a bigger cam in there
