The Stovebolt Site Forums The Shop Area Engine Shop Unknown engine stamping

I just bought a 1954 1 ton 3942 Grumman step van and the 6 cylinder motor is stamped at distributor pad : "53 S 12 9P". It appears to be a 235. I have not seen a number like that. Does it ring a bell for anyone? It's so grimey I haven't been able to get to any casting numbers yet. Thanks.

bigblack'74,

Only way to be sure is get past the grime for casting numbers and pictures for folks to lend a hand.

Can you update with a picture of the stamp "53 S 12" and where exactly it's located???

More will chime in as you can provide pics.

As I mentioned it's on the pad behind the distributor where they are all located. I don't have any pictures. It's extremely tight down in there on the vans. I am confident that's the number. I will look at it again in the next week. Thanks.

There are not enough numbers/letters to be a 1953 engine made in the US, 1953 still had engine serial numbers as part of the complete engine code...

Might be a replacement or rebuilt engine???

Mike B

I updated the number. I took a picture but have no way to post it.

Photo posting instructions are in the left margin of every page.

See picture

The updated number provided does not cross reference to anything I can find through on-line resources.

Thinking only way to figure more out from here is going to be cleaning and finding your block and head casting codes/casting dates.

Sorry not more helpful!

Update what you find when you can and we can try to provide more info.

Good luck!

Like Dan said, we need the casting number.

If it's a Chevrolet motor it will be found just above the oil pan on the passenger side at the front of the block in a recessed area...it might be buried under grease and dirt.

Your number kind of looks like it's a GMC number to me at first glance...

Mike B

Those stamped numbers from op are perfectly aligned
I’ve never seen factory stamp numbers that perfect
I have a collection of stamped characters from different production plants on my computer I’ll try to match the style but I suspect it won’t match any of the common facilities
-s

This is why I posted the question. I have owned many 216, 235, and 261 and have never seen any number like that. I will attempt to find some casting numbers. Its significantly more difficult with the van body to see anything. I am most interested in what the stamping means however. Thanks.

I was able to sneak over in the dark and got two head casting numbers. The only casting numbers fore or aft of the fuel pump is "12 and GM". Taking the starter out to see the casting numbers is not a possibility right now. I can disassemble all of the stuff in the way to remove the valve cover to see date code hopefully this week sometime.

That B 4 7 over the spark plug looks like a Feb 04, 19x7 casting date to me. The 848 head was made from 1956-62 so the casting date would be Feb 4, 1957

GMC stamped numbers behind distributor on pass side always start with displacement, I e 270xxxx.

Ed

The "848" head definitely indicates that it is at least a "235" later model head as noted by Bill H above.

Not saying so for sure, but this may indicate the numbers you have stamped in the block pad may quite possibly be a re-stamp for some reason.

Does this "engine" number show up anywhere on your title/registration documentation???

Maybe the picture attached below will help locate your casting code?

Does not require removal of the starter to find the expected 7-digit casting code.

Will wait for further updates.

Good luck in your search!!!

The rig is titled thru the serial number on the body. Nothing shows up from the engine number. I will go back tomorrow and see if there is anything by the fuel pump. When I scrubbed it all off at 4am I didn't see a thing. It's probably impossible to get pics down that low.

Well at least the 848 head confirms it's a Chevrolet engine...that's a start and knowing the head is dated 1957 indicates the engine has had work done to it.

If it was a fleet truck the stamped number could mean it's a rebuild and that's their tracking number, but the numbers look to straight and neat to be hand stamped.

Mike B

There is a " 16" casting in front of the distributor, " 12" over "GM" in front of fuel pump and " CONV 4" barely visible behind the starter. That is absolutely all casting on the motor that's currently visible.

Based on your latest batch of picture, here is a new picture found after further web searching.

I clued in on the first of your pics which shows a different side mount bolt pattern than the one in my previous picture.

This new picture displays the same side mounting bosses as yours, but shows this particular year group of block (50-54) has the casting number forward of the fuel pump mount point (down close to the oil pan rail area in right side of photo).

Thinking the elusive casting number is just above the oil pan flange in your last pic, and you may need an angled inspection mirror to see into that spot.

Sorry this is turning out so difficult, but hoping this will help finally locate the rascal.

Copy that. I will check up front tomorrow. It's so deep in there with this van chassis, you cannot see hardly anything. I believe it is (or was) a full pressure motor because of the 60 psi gauge. I am confident that has not been changed.

See attached. That denotes 1955 I think. I believe that's the original engine based on the trucks serial number. Chevrolet has serial numbered the van as a 1955 but titled as 1954. The van body is the 1954 earlier version without the exterior radiator fill access. I assume they used up the bodies on whatever chassis Chevrolet sold them, until they were gone. So technically the drive train is 1955 but the body/dash ect. is a 1954. I still would like to know what the stamping means? Thanks.

You found the "casting number" rascal - woohoo!

Further search of "engine block" casting number info on the web (referred to at least 6 different sources), indicates your engine block is primarily identified as:

1955 First series 235 (Excluding Powerglide)

Some of the sources were less defined, identifying it just as a '53-'55 235.

From this info, sounds very much like you "may" have the original engine block, especially considering the info you have on build and registration data. It should also be mentioned that your "head" casting number identified it as a later (1957) 235 head. Evidence of repairs done at some point along the line.

The "odd stamped serial number" could be a number stamped by the "Stepvan" manufacturer. Maybe there are other "Stepvan" owners that have some historical info to help???

Am sure others will chime in with more info or leads as they can.

If nothing else, at least you know exactly what you have to start working on.

Something I also noticed was Olson Grumman serial number'd the body separately from the chassis serial number. Consequently that serial number is NOT the same stamped number on the block. It infact is nothing like the engine stamping.