I fabricated a thick steel plate that fits onto the back of the block with the bell housing attaching bolts and mounts my Van Norman cylinder boring bar to center up in the rear main bearing bore. That machine dates back to the late 1950s. I can be making chips with less than an hour of setup time. The whole works is portable- - - -I machined two blocks for lip seals at the "Homecoming" at Grigg's place a while back.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!