Suburban rear seat hold down hardware

[Brad54]

I've got a '62 Suburban, and have a stock rear seat with one of the original clamps that hold the seat to the "keyholes" in the floor. It's a simple carriage bolt with a wing nut--the bolt head slips into the keyhole and slides forward to the thin part of the hole, the shaft of the bolt goes through holes in the seat frame, and the wingnut goes on top of the seat frame tubing to hold the seat to the floor.
HOWEVER, my one single mount also came with an original piece that straddles the seat frame tubing, and is flat on top for the wing nut to seat on. It distributes the force of the clamp over a larger area, and gives a much firmer bite to the wingnut. The original one I have seems to be made of brass. I believe they used the softer brass instead of steel so it didn't work-harden the seat frame or crack the seat frame. The softer material absorbed any vibration and stress before the thin wall tubing of the frame would crack. I think it'll eliminate one more source for vibrations and rattles, as the wingnut isn't likely to back off the flat bracket.

I've fabricated a new set of these clamps out of aluminun for my truck. I'm going to turn Boy Wonder (my 12-year-old) loose on the power tools, and we're going to start making them to sell as complete kits: bolts, wing nuts, washers, lock washers and the aluminum clamp.

My immediate target is '60-'66 trucks, because I know this fits. At some point, they started putting different rear seat mounting tracks in some of the Suburbans--I think the later '64-up GMCs, but I'm not sure what year that was, and if it's only GMC.

Also, I saw a pic of the bracket from an AD Suburban, and it looks identical. Can anyone tell me what years they started this bracket style in Suburbans? What'd they use in the '40s?

The two critical factors I'd need to know for the AD suburbans would be the diameter of the bolt head (so it fits in the keyhole), and the diameter of the tubing for the seat frame.

Can anybody give me the info on:
A) when they went to tracks in the '60s
B) how far back they started using this type of seat hold down in Suburbans
C) the bolt head diameter and frame diameter in AD Suburbans
D) Do you think there's a market for these clamps? I'm not looking to make it rich, but I'm also the kind of guy who still stops to pick pennies up off the ground. One or two don't amount to much, but they add up. If I can sell some of these, I'll have a little money to do other projects like front sway bars for '60-62 trucks.

I appreciate any input,

-Brad