I find the "Chevrolet Pickup Red Book" (Motorbooks International) useful although there are gaps.

In spite of that, the 1949 under Engine Suffixes for the 3600/3800 says :

AGCA - 216.5 I-6 1bbl 90 hp- three/four speed manual

It has the same description for AGCM but does not mention AGEA.

The AGCA is not further broken down. I assume the AGCA would have been stamped behind the distributor but as a prefix not a suffix.

Maybe, swapping the "C" for an "E" would be for a 235. Were 235's in Loadmaster trucks, not Thriftmasters?

I checked out EBay and just bought another copy of the Red Book for $6.38 (free ship) that I'll give to my brother-in-law.

By the way, your 3600 would have cost $1372 list back in the day.
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Last edited by Wally / Montana; 04/27/2020 3:13 PM.
1948 3/4-Ton 5-Window Flatbed Chevrolet

34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.