JAD... J = 1951 A = Passenger car D = unknown, if it is a P it was mfd in the Tonawanda plant and with a HD clutch. The D might indicate a PowerGlide 235 engine. I’m not sure.
F56Y is a '56 passenger car 235 (140 HP rated) manufactured in Flint, MI, originally mated to a Powerglide (would have had hydraulic lifters).
F1208AE (an I was often used to stamp a one), would be a '58 (or later) passenger car 235, manufactured in Flint, on December 8th (year would need to be determined from the date code near the starter), originally with HD clutch. This info is from my '58 Chevy Master Parts catalog, and if the block date code is after '58, the AE suffix would need to be double-checked.
Tim decoded the F255X - '55 second series truck, 235 (120 HP rated, would have solid valve lifters, if still original).
JAD is a '51 (RPO 317) 235 (105 HP rated), passenger car service, manufactured in the Flint plant, and as Frank suspected, it would have been mated to a Powerglide, and had hydraulic lifters. It also is a "low pressure" splash/spray oiled, Babbitt rod bearing engine. This info is from the '51 Chevy car VIK from the GM Heritage Center site archives. All of the other engines are all "full pressure" engines with pressure-oiled insert rod bearings, and perhaps preferable, by comparison.
F54Z is a 235 (115 HP rated) manufactured in Flint, from a '54 passenger car with standard transmission (as indicated by the Z suffix). In '54, cars with standard transmissions came with solid lifters, and the block is not factory drilled for the oil gallery needed to support hydraulic lifters. Only 235s in Powerglide equipped cars in '50-'55 came with hydraulic lifters, and had the corresponding gallery drilled at the factory ('55 was the transition year, so '55 blocks need to be double checked, drilled or not drilled) . I'm running an F54Z engine in my '53, and it is a sweet running engine.
Jumping out of order, the F56Z is a '56 passenger car 235 (140 HP rated), which follows the same decoding pattern as the F54Z, and except that it would have come with hydraulic lifters, regardless the transmission type originally fitted.
F302JC (assuming it's a Chevy engine, not a GMC as Frank suggested), is a '58 or later 235 Thriftmaster truck engine from a 4000 series, with HD clutch. If the block date code is later than '58, the JC suffix should be double checked for model application. Info again from the '58 Chevy Master parts catalog. 302 would indicate a March 2nd manufacturing date.
FWIW, the '54 engine might be the most straight forward swap into your '53 (water pump is the same older style), but engine condition should dictate which may be better.
There was a low-pressure 235 (1937-1953) and a high-pressure 235 (1954-1962/63?). The high-pressure 235 was introduced in 1954 (the same year the 261 became available in big Chevrolet trucks).
Good-day, I'm hoping that the vast wisdom on this forum can provide some answers for me about my truck engine. My son and I have started working on a 1949 Chev 3100 that I originally bought when I was a kid, we're starting by rebuilding the engine and both myself and the owner of the engine shop are having some trouble narrowing down the exact engine I have. It's definitely not original for the truck, it has a 4 bolt valve cover and hydraulic lifters. The block casting number is 3837004 (which if my online research is correct tells me that it's made between 55-57), on the pad behind the distributor is stamped C270610, there is no date code or CON number on the block behind the starter. The problem we are having is ordering parts for it, even with the 55-57 range there are I believe 4 different kits available with slight differences in main/rod bearings, valves and oil pump. This is the engine that was in the truck when I bought it 20 years ago, and it came with a manual transmission (floor shift) - but with that year range and having hydraulic lifters I'm thinking that it was likely originally a car engine on a powerglide? I'm not sure if there are any differences in being able to bolt up a standard to an engine that was originally built with a PG that would give me some indication. Honestly in all my online research I haven't come across a single reference to an engine code with a 'C' prefix, ironically my engine builder has another customer's 235 in his shop right now and it's out of a 59' truck with a code of C414477 and he believes it's his original engine, it also doesn't have the date code castings on the block behind the starter. I am located in Alberta, Canada - does the C prefix indicate a Canadian built engine? Any help would be very appreciated, we're just getting this project off the ground and would like to keep some momentum going.
