Tripod mount identification

Hey folks,
About a year ago I acquired an older (80's-90's?) tripod from a thrift store for three dollars. I never messed with it until recently after acquiring my F5 (almost 6lbs with lens) and stopped trusting my flimsy old one. There are no defining features and I wasn't able to find anything online from the text on the side. On the top there are 4 screw holes, they are not in a square shape (one side is slightly longer than the other). I have absolutely no idea how to figure out what mounting plate or head would fit onto this. Please help!

It's missing the top of the head. You will likely have more luck abandoning it and getting a sturdier name brand tripod. My experience is that cheap tripods that don't use round tubing for the legs are not rigid enough to be worth much. If you don't mind a little weight, and want a larger tripod, used tripods often sell at a large discount from new. For ex many of the Bogen/Manfrotto models.

That looks like so many of the thrift store tripods I see.
It is missing critical parts, and as it isn't one of the major brands, the chance of finding those missing parts is minimal.
Sorry for the disappointment.

That would not work with F5

If that's set up like my eBay carbon fiber tripod -- which means you should be able to remove the pan-tilt from the standard 1/4-20 screw and replace it with another pan-tilt head with a standard quick-release mount -- or just screw the 1/4-20 into the camera's threaded socket, if it has any way to level the camera.