[Larry Hill]

The block maybe be made from bubble gum aluminum but the machine work is very good. I?ve collected some destroyed blocks that I rob parts or cut up to better understand what I?m working with. To drill and tap the block I used old main caps that fit my block amazingly well. Front to back, left to right (they are cross bolted and doweled), and housing bore is close.
Made a concentric sleeve for the cap. OD of the sleeve fit ID of cap ID of sleeve fit tap drill. The second cap was drilled just under the the OD of the threads of the tap. While the second cap was in the mill after drilling, a center was added to support the end of the tap to keep it straight and centered during the tapping operation.
By having the cap loosely taped it forced the tap to tap the hole straight and perpendicular. I had to modify a insert tap to be a bottom tap to use all of the insert. I did not want to give up the last two threads.
All drilling was done with a hand drill on the block. The only things I had to observe was speed, feed, and depth.