360 pans use a smaller gasket on the rear of the pan and are not interchangeable with the 273/318/340...
The pans with the six nubs for the end seals were not used after 69, so it will fit a 273 for sure... It will fit a 273/318/340...
In 70 they changed to the two nub end seals....
Here'a s thread that has some info on oil pans:
How to ID a Small Block Oil Pan 60's - 80's
