Another 273 to 318 swap questions

WAIT a minute-----------

Is this a stick or auto?

The older torque converters and crank flanges were smaller than later, meaning you need a bushing ring in the newer engine crank recess to center the older, smaller converter

If this is a stick make SURE the crank is drilled deep enough for the input shaft. A common "cure" used to be to cut 3/8" or so off the input shaft. The crank hole won't be finished completely, and you'll either need an undersized pilot, have the pilot hole finished, or use a later Jeep style pilot which fits in the converter crank hole

So far as 273/318/360--and don't forget 340 -- some of them have different block ears, and you need the proper engine brackets. I actually adapted my original 273 brackets to fit a 360

There are NO exhaust clearance issues except----

You must have the proper manifolds to fit the BODY, not say, truck, motorhome, C body, etc

or use headers, which have their own problems regardless of engine size.

You'll need a center/ front sump pan, so depending on what the new engine came out of, you may need to use the 273 pan. It will NOT however, fit a 360.

Otherwise, any of the small blocks fit where "any" of them came out of.