[54belair]

That particular gear is mid to late 60's-----I believe it is 3 1/2 turns. Same as mine-----look to see what type fittings it has----if its for flaired fitting its a 60's style.
FYI--- Ill give you a quick story about gears!! most rebuilders use the same gear for years from about 64 all the way up to the early 80's. They tell you they are direct fit----but that's not always true there is a slight diff. in mounting with the later gear and also the later gear does have O ring fittings.
I have ordered and sent back three gears because they keep sending later model castings (which I don't want), the parts store and the rebuilder cover their rears by saying "it'll fit----------just do this or do that or replace your lines and it'll fit fine. The part number you have was used up till about the end of 72.