71 dodge 360 running motor.

Mileage? All OEM 360's had 1.88" intake valves, even when they started the 4 barrels in '74. But Chrysler did use the same 915 castings, just machined differently based on application, 340-4 and 340-6 engines for a few years!

That is the first model year for the 360 and they are sought after. But the thicker bores are an ongoing debate. I never had any sonic-checked, but it can't hurt. Core shift is a concern for any engine when investing a lot and/or going big on the overbore.