Is this a 340 or 360 pan? Need one for my 5.9.

It looks like a 360 car pan. The rear seal is area is smaller & narrower than the front. If it were a 273/318/340 pan, the rear seal would be the same as the front.

If that's an OEM pan, there should be bold 3# stamp that would provide more details (year & model use) if someone knows the numbers.