swap 170 to 225? (FNG warning)

The only fly in the ointment I can think of is the crankshaft register. This changed in '68. If the 170 is a '67 or older and the 225 is a '68 or newer you will need a different flywheel for the 225. If both engines are '68 or newer it's a straight swap, and if both engines are '67 or older it's a straight swap. If the 225 doesn't have a pilot bushing the crank will be drilled for it. Most of them have a bushing whether it was used or not. If the 225 is going into a '66 or older car you will also need to use the 170 oil pan, pick up, and dipstick. Hope this helps.