[Ed Snyder]

Originally Posted by jgpnashville

I found and scanned the Protect-O-Plate from my 1967 K15 today and I'm trying to figure out what all the numbers mean.
I know the VIN is the first two numbers and "305E" is the engine. I think 464657 is the serial number from the engine.
"RXSTD" would seem to refer to the rear axle as being a standard and "3.54" would be the rear ratio, right?
"ID56885" should match the rear axle serial #.
"TRSM318" refers to the transmission type, which I am pretty sure is an SM420 (manual 4-speed with 7.05:1 low first gear). What does the "P" after "GMC" mean? It doesn't seem to line up with anything.

Any ideas? Have I gotten anything wrong in the list above?

The SM318 is a three speed transmission. If you've got an NP420 four speed now, a previous owner must have replaced the three speed. You can find more VIN info at http://6066gmcguy.com/VinNumber.html and http://6066gmcguy.com/GMC-vin-list-6769.html