You might check for a number on the frame just in front of the right front spring bracket.

If there were or is a serial number that is the most likely place for it.

I do not have an 600 series yet, both my 1953 450's have serial numbers on the right front frame. And those numbers match the S/N's on the door plate and glove box lid.

The S/N does not match the engine numbers, but rather the frame numbers.

Here in California I have found Chevy and GMC trucks were registered by the engine number in some places, and in other places the trucks were registered by the S/N on the frame and door plate. In some cases it was the dealers that registered the truck and in some cases it was the DMV. There was no consistency as to how it was done back then. No VIN numbers were used.

I have changed all the registrations on my trucks to the S/N on the frame and door plates.




Last edited by GMCPic; 01/25/2014 12:55 AM.
Dance like no one is watching,
Sing like no one is listening,
Love like you've never been hurt.

1948 GMC FC101 1/2t Pickup w/270 and SM420
1948 GMC FC253 1t Factory 80"x9' Flatbed Dually
1948 Chevy COE 2 Ton 8'x15' Flatbed
1950 GMC 354-24 2 Ton 8'X12' Flatbed w/Dump Hoist
1953 GMC 454-30 3 Ton 8'x14' Flatbed w/Dump Hoist
1953 GMC 454-30 3 Ton Cab and Chassis
1942 Clarkator 6 MILL-44 Heavy Aircraft Tug
1942 Ford (9N) Moto Tug with 1/2 yard Loader
1947 Oliver OC3 HG-42 Tract-Crawler Bull Dozier w/6' Blade