Quote: Vic... looks like they damn near missed the boss area on the upper head bolt holes on the first and third holes looks like a nice block.... also what are the holes above each lifter bores... maybe oil holes(oil letter inners )
Mike, It's my belief, the XR blocks were initially cast soley for P-7 heads. (XR-2) On the XR-2 version, the bolt holes are located in the center of the bosses. Notice the extra head bolt boss at the rear of the block. (2nd picture) P-7 heads use 20 studs.
I asked Kent about machining the XR to accept the P-5 HEMI. I think it's possible but, doubt it will happen. 430"+ P-5 HEMI??!!
Holes drilled to the inside of the lifter bores are pilot holes to the oil feed. Then the pre-drilled bushings were pressed in and honed. Just happens to be the way this particular machinist chose to do it.
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