The Stovebolt Site Forums The Shop Area General Truck Talk 1941 Truck Engine ID question

Just picked up a 1941 Chevrolet 1 ton. Im having some diffucukty decoding this engine. Any ideas. Thanks.

AAF491402

AAF is the prefix for 1941 3/4 ton truck engines built at the Flint plant. The serial numbers start with 1001.

It appears from the 1941 Vehicle Info Kit LINK, that there were no 1 ton truck, just 1/2, ton, 3/4 ton and 1-1/2 ton (conventional and Cab-over-engine)

FarNorth, Kevin's basic info on first glance of the document looks correct, but a little deeper reading (just clarifying info here Kevin ) shows there is a "technically" 1 Ton rated truck for 1941. It used the 134.5 inch 1-1/2 Ton chassis, but when equipped with RPO (couldn't find an RPO listing to know what number?) with lighter rated rear springs and 6" x 20" wheels front and rear, got a 1 Ton rating designation. It doesn't show a different model number or serial number designation, but does indicate there would have been a 1 Ton rated data plate affixed to correspond with the adjusted GVW. Extract pictures from the PDF with these detail are below. There are other references throughout the document on 1 Ton related data to support the info too. Got some pictures to share of your truck???

PS: Maybe share with us the trucks serial number so we can look into that with the resource document too?

VIN#: 5AN018297

That looks like an engine serial number. Is that what's on the title? Maybe used in place of the vehicle serial number. What's on the plate under the hood on the right side?
5 - Kansas City, MO plant
AN - Conventional HD truck engine built at Tonawanda
01 - January build month
8297 - serial number - 7297th engine off the line.

Sorry for the confusion. Yes, the AAF481402 is whats stamped on the engine block. The VIN plate is 5AN018297, the plate looks like it may be not original. Title has the 5AN018297 on it.

FarNorth - Sorry to take a bit to get back to your post. I followed up on Kevin's idea that the "VIN" 5AN018297 does possibly seem to be an engine number, so I dug back into the GM Heritage data file to see what may be found to try and clear that up.

The 1941 Chevrolet Truck data PDF shows more detail in various places, some that seem to be difficult to follow/understand. In the 1st page of "Basic Model Information" (pic 1 below) it indicates that a One ton truck (Vehicle Type) identified as Model Name: One Ton (RPO) with a 134-1/2" wheelbase chassis would have been identified with the Serial Letters: YR. The Serial Letters "AN" are shown to apply to a 3/4 ton Panel truck on a 134-1/2" wheelbase chassis that is also further identified by the designation "TSL".

Could it be that your "AN" Serial Letter sequence data plate was originally on a Panel Truck??? That Panel would have used the same long 134-1/2 inch wheelbase chassis as the 1 ton pickup. That may account for your mention above of the truck having a possibly non-original "VIN plate".

If you look further in the GM Heritage document, in the section "Unit Serial Numbers" (see pic 2 below), that information would have your "VIN" decode as:

5 = Kansas City Plant
AN* = 1941 3/4 TSL (3/4 Ton Special Panel with 134-1/2" wheelbase) *year/model taken from the first pictured "Serial Letters" info
01 = January (build month)
8297 - 7297th truck built at the Kansas City Plant for model year 1941

Anyhow, have you measured the wheel base to confirm it's 134-1/2"??? Feel free to continue to ask questions as you like and we'll do our best to help out.

I think this would make sense, cause the VIN plate does not look factory to me, so maybe they used a VIN number from something else? I have a 1946 GMC truck that I'm wanting to restore that was my Great Grandfathers which he bought in 1947 and the VIN plate on it is definitely factory. There may be differences in the US built and Canadian built trucks though, my GM is a Canadian built truck. My 46 is a factory 1 ton 9ft express box same as this 41 Chevrolet I just picked up, I should note that I did purchase this 41 Chevy from the US. I'll attach a picture of the factory 46 VIN plate and the one on my 41.

Also to note that both of my trucks are 134" wheelbase.

What do the fasteners look like on the 1941 truck data plate? That would be a clue as to whether it has been replaced. The overall look of your 1941 data plate seems authentic, compared to the attached pic of a reproduction one. They were aluminum with most data painted on and weight and serial number stamped into the metal, which appears to be all that's left visible on yours. The "58" would indicate 5800 lb gross weight capacity, which corresponds with a 3/4 ton Special truck.

This is starting to make sense now klhansen, as the plates do look similar also the weight table shows the 3/4 ton as having 7.00/17 tires which it does have, mounted on 6 stud wheels. Interesting to note though that my GMC 1 ton has 7.50/17 inch tires mounted on 8 stud wheels. What would "special truck" mean, could it be that it came with the 9ft express box that was usually only found on the 1 ton models like my 46?

Looking at the fastener on your 1941 data plate (I didn't see it at first), it looks original with the small combo clutch/hex head. It might be possible that the body has been switched out sometime in the past 80+ years to a different chassis. A lot can happen in that time period.
Likely more study would be necessary to nail it down. It used to be that GM would send you an information packet if you sent them your serial number, but I don't think that's available now. I do have a contact somewhere for a lady who works at the GM Heritage Center. If you'd like I could track that down for you.

I'm beginning to think that maybe the cab was swapped out with a different one at some point, but its hard to say, these old trucks seemed to have a whole host of different styles and such as I'm finding out quickly here. And it seems to get really confusing when you get into the 3/4 & 1 ton area. The truck does look good though and is a complete unit with the spare tire and all. Fenders and box are in really nice condition. The 9ft express box and fenders are what I bought it for as they are pretty much non existent as used ones and nobody makes the fenders or boxes for the 9ft style. I was about to walk away from the whole restoration until I found this truck with everything I need.

Your Body serial number plate looks real to me with the correct fasteners and having the Plant/Series/Month stamped larger than the unit number.

My Parts Books (1951 and 1959) shows "AN" as "1941, 134-1/2", Commercial 1-ton Truck".

"SPECIAL" could mean the GVW on a particular series was either increased or decreased. In your case the 3/4 ton Series "AL" or "AM" was basically increased to be a 1-ton and designated "AN". My parts books also don't show any 3/4-ton trucks having the 134-1/2" wheelbase, they were all 125".

To me it looks like you have a match made in heaven...both the engine and body numbers look right for a 1941 1-ton.

Mike B

So did we ever determine what the engine was, since that was the original question? Or did I miss it?

Yeah, my original question got buried by chasing down the chassis vin. I guess i would also like to know, is this engine a 216 or would it be something larger like a 228? Thanks.

The Vehicle Info Kit says either a 216 or 235 engine would be installed.
A 3/4 Ton Special would have had a 216.
For larger trucks (1-1/2 ton), a 235 was available as an option.

FarNorth, Before we switch back to the engine ID info, I just wanted to add that after reading Mike B's input above, indicating that the "AN" designation is correct for a 1941 1 Ton, I can back his info up as both my 1946 and 1948 Master Parts Books say the same thing. Looks like the GM Heritage Chevrolet data file isn't 100% accurate.

On your engine ID, below is another extract from the GM Heritage site 1941 Chevrolet Truck data specifically for the engine ID info. The "AAF" designation does show in that chart as falling under all 3/4 Ton truck categories, which I would think may include your 1 Ton rated truck as we discussed that being the long chassis, but with lighter rated springs and the smaller 6 x 20 wheels. The info doesn't say the "AAF" is a 216, but in footnotes on the bottom of the page for the Conventional Trucks/School Buses and COE's, they got assigned a different model ID designation to them to indicate they had 235's installed as an RPO.

That being said, the best info I can find says your "AAF" engine is a 216. I did one more check in this resource Chevrolet Owners Manuals. In looking at the 1940 and 1942 Owners books, both indicate that 3/4 Ton trucks were equipped with 216's. I couldn't locate a 1941 Owners manual to check that info to be sure.

Perhaps there is a fellow 'Bolter with an original 1941 Owners book that can look it up and confirm???

Sorry - Kevin beat me to the post button with his answer.

Per my Parts Books the 1941 235 engines were designated as either "AG" or "AL" (the difference being conventional or COE).

Mike B

OOPS, I see I repeated what Dan showed above...

One quick identifying feature of the spray-oiler 235 engine block- - - - -it's 1/8" taller than a 216 when measured from the main bearing centerline to the cylinder head surface. That compensates for the increased crankshaft stroke while using the same connecting rods and compression height of the pistons. Unless the block is stripped down, that difference will be hard to measure, however. A 235 also has a 3 9/16" bore instead of the 3 1/2" bore size of the 216.
Jerry

I want to thank all of you for all of the answers to my questions it’s much appreciated, I finally know what I have. These stovebolt trucks are new to me so I’ll likely have more questions as I move along. Thanks.

FarNorth, Glad to hear things are coming together for you somewhat. We are here to help in whatever you need. Remember to post your questions in the most on-topic section of The SHOPS. If you are not sure where, we'll move it to the best place. It's part of what we do. Keeping it organized helps others with similar questions.