I suspect that the block may be a replacement. The serial numbers as you posted are very different from mine. Did you take them from the flat area just in front of the starter?
Mine are: Engine Code: FI20A (serial number) F - Flint, MI engine plant 1 = January 20 = 20th A = regular production engine with 3-speed or overdrive
If you look at mine, the stamp is somewhat uniform. Yours look like they were hand stamped.
I’m sure some of our experts can give you more info.
Last edited by Phak1; 11/20/20191:32 AM.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
i keep a list of castings and where they are used, your was not on it, so i google searched a bit and compared the stamp markings to known samples. block casting 3733949 is listed in a few places as 1953-55 235 USA
reading between the lines, and i might be totally wrong here, it appears that this engine may have been from factory paired only with manual transmission vehicles and had solid lifters? but the engine was sold alone as a replacement engine with either solid or hydraulic lifters to at least 1957 according to one post someone made online that i can't find now.
also to make it more confusing for you... the stamp marks look a lot like the Canadian engine serials, the shape of the 6 looks like Canadian engine markings. USA 6 is not curved. also the fact that it has just 6 numbers and no letters at all, that's how many of my truck engine serials look like up in Canada. perhaps this block was made up in Canada years later in 1959?
lets see if others can shed light on the mystery. -s
That block casting number is shown in my 1959 Parts Book as being available for "ALL 1954 235's and Comm 1955 1st series". Chevrolet had to keep making this block because newer 235's wouldn't work in a 1954 due to the water pump/fan height....
So, I'm with others...you have a replacement block with a hand stamped number.
Does that engine serial number match anything else on the truck or title? Could be an engine re-builders serial number or ID???
Mike B
Mike Boteler
1956 Chevy 3100 Resto Rod 1952 Willys M38 Army Jeep 1983 Jeep CJ7 Laredo 1984 Jeep CJ7 +++++ Silver Spring, MD
don't let the terrible spacing fool you, my factory engines in Canada look like hand stamped, numbers not in a line example attached
but yeah, it could be a coincidence and you have a replacement engine, i can't find evidence yet of that block in Canada, so we don't yet have all the facts in this mystery. -s
I have seen a factory replacement engine for the 1954/55 1st engine, and it used the 1955 2nd through 1962 pan. That pan is not straight down both pan rails, like all 1955 1st and earlier, it bulges out some on the oil pump/distributor side.
Very interesting response. I think this makes sense. The hand stamped serial# mmmm - that could have been a GM procedure for "parts" engines made after year of original manufacture? Thank You! For great info. Sounds good anyway - I'm going with it. Ron A
John's 261 engine we rebuilt a while back was a high water pump type normally associated with 1954-55 production. However, it has a 1959 casting date and a blank number pad by the distributor, and the main bearing bores are machined for post-1955 mains. It has to be a factory-replacement block cast using the early mold, but machined to post-55 specifications. That made fitting the main bearings an adventure- - - -requiring a little block modification to accomodate the early style mains we had on hand! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I believe John included some pics of the block, including the casting number and manufacture date in the article he wrote up in the "after action" report. That was supposed to be a weekend project that stretched out to about 8-10 days when we discovered a damaged piston and had to order a replacement.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
With the casting date of 1959, it's almost got to be a replacement block designed for a dealer or aftermarket engine change for a worn out or damaged original engine. Quite often, those replacement blocks came with a blank pad behind the distributor so the shop could duplicate the original engine number. That was important in states where a vehicle was titled using the engine number, not the chassis or body number. In that case, the casting number will be for the 54 engine, but the casting date will be 59. Most likely, it will be machined to accept the later model main bearings, and will NOT have shims between the main caps and the block. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I was told that when a replacement engine was issued, GM would send the mechanic a stamping die set to transfer the original engine serial numbers to the new replacement engine. When done, the mechanic would send the stamping die set back to GM Headquarters.
I was wondering the same thing, a single digit number for date code year seams a bit confusing. I.E. 54 or 64
This is normally not an issue as most casting numbers don't last more than a few years and almost never over 10 years. But, due to the water pump height of this block vehicles needing this couldn't use a newer block. So they either cast a bunch of them in the late 50's and still had inventory to burn up or they continued casting them due to continued demand? Either way, it's still in the book as of 1969 and maybe beyond...that's my newest book...
Mike B
Mike Boteler
1956 Chevy 3100 Resto Rod 1952 Willys M38 Army Jeep 1983 Jeep CJ7 Laredo 1984 Jeep CJ7 +++++ Silver Spring, MD
