Thompson Speedway Swap Meet: Flywheel Help

Hey all, this weekend I'm going to the swap meet in Thompson Connecticut for the first time :-D. I have a cast crank 340 that I am doing a 4spd conversion and I need a flywheel and bell housing w/ clutch fork. What should I look for to know which is right? What are the markings on the externally balanced 340 flywheel? Will any small block 340 bell housing with O/D work? Or are the clutch forks different? Should I bring some calipers to measure the bearing retainer opening diameter?

Edit: OK so just found out that I can also use a flywheel from an internally balanced 318 or 340 as long as I get it drilled. From the picture that CrackedBack posted it looks like it's just 1 hole?