my new 360...

The shim space is easiest to take up with a spare bolt, washers will work as well.

The first 2 years of the 273 (IIRC) have an intake bolt that is smaller @ 5/16 instead of the bigger 3/8 size. Also, when you bolt the intake onto the head, the angle of the bolt is at a different angle.

The smaller 7-1/4 rear should be replaced with a 8-1/4 or 8-3/4 size rear for longevity. If you have the driveshaft that came with the car, it will need to be shortened to work with a 727 trans and/or a different sized rear end.

Also like they said, the 360 oil pan is different from the other oil pans from the rest of the small block family. A truck pan will not work, it must be a car pan.