It would appear when Mopar machined their after market blocks they opened the bores to approx. 0.906” for the 0.904” lifter. This is ok for a flat tappet lifter however, most of the solid roller lifters available are 0.903” diameter, which is where the extra clearence is from. I guess they figure people building a solid roller will bush the block because of the uncovering of the oil gallery problem. I heard of this with the Mopar a Hemi blocks. Wonder if the 48 degree blocks are the same?
What block are you using? I have 3 X blocks, one of which was brand new and an R block and none of them has lifter bores that big.
