will any SB fuel pump work on a 65 273

The 340 pumps put out about 2 psi more than the others, so you gotta be sure that your needle(s) can handle that. I measured 7psi on a 340 once. Same gauge reads 3 to 4 on the others.

and sealed pumps are not clockable. Some have threaded ports and some have hose-nipples, and some have one of each; But they all bolt onto the pad provided for them. and all can be made to work, albeit some easier than others.

The thing is to properly diagnose your system to make sure that you actually need a pump.