Old GM Gear Identification Cast Number 5153271

Got an Old Military Packed Gear Stamped 5153271 GM All other Numbers are on the little tag in one of the picsAttachment 61838Attachment 61839Attachment 61840Attachment 61841

So no ideas??

Being as it is a balanced item, it is probably meant to run at a fairly high RPM; the four holes equal distance from the center bore look to be for some sort of flange attachment, but that is speculation on my part. My first thought was that it was for use in a PTO application, as it is "military packed", but again, speculation. Looking at the tag that you picture, I see the first line says it is a "Lo" Gear, and the .409 might be the bore diameter?? The fourth line says NSF Mech. P(ump)(?). So, I speculate that it is a drive gear for some sort of high speed, high pressure pump. Purely conjecture on my part, but I couldn't resist opining on your question. The real possibilities are almost endless.

I thought I posted earlier but I guess I pushed the wrong button again..GM in-line 6 cam gear

I concede to the authority, Charlie, actually, I never even considered that. I didn't look as closely as I should have at the last picture, or I would have noted the size, and might have had that thought, but somehow, I thought it was bigger.

Cam gear? i got a lot of NOS Cam gears for inline 6's this thing weighs about 6 times as much as any of my cam gears and is significantly wider

I don't think its a cam gear--the size from the pic with the square looks like its pretty big and also the cam gears aren't counter balanced like that=========I would think that its off a shaft driving something like a single cylinder air compressor from a brake system----counter balanceing the air crank--

it's making sense w/ the military packed box it came in. I've had a lot of engine heads look at it and so far nobodies been able to figure it out. was really hoping the casting number was going to come in handy to help narrow this down. really would like to figure out what it's off of