In the decidedly imperfect world of real life, while making a living doing, and teaching automotive machine work, for 50+ years, I routinely bored all kinds of engines either 187 thousandths or 250 thousandths to install sleeves. Sometimes I hit water, most of the time I didn't. Either way, we installed the sleeve and assembled the engine. Very few, if any, gave any problems. I watched my father bore several flathead Ford engines 250 thousandths oversize without sleeving them, and run 11.5:1 compression on alcohol and peroxide, at over 6K RPM . He would offset the center cylinders a few thousandths away from a thin area where the exhaust passage went between them, and narrow the top of the connecting rods to let the pistons center up in their bores.
There's a lot that can be done to make engines do what we want them to do, once we get over being timid about whittling on heads, blocks, and crankshafts.
Jerry
