One list of stamped #s by prefix I have for 53 shows:
LAA orM 235 reg prod passenger.
LAC or P-235 w/10 3/4 clutch.
LAE or R- 235 w/powerglide and pwr steering.
LAF- 235 w/alum timing gear, pass.
LAQ- 235w/powerglide pass.

There are others, these are the only beginning with LA.

It's easier to get forgiveness than permission!
1946 1/2-Ton Chevy
1953 Chevy 3/4-ton Factory Stakebed