I have a '53 Chevy with what I thought was the original 235, but after purchasing an oil pan gasket from NAPA, I found it did not fit.

Luckily the counter person checked later years, and found a '55 (second series-- Truck??) Oil pan gasket that was right-- it has the slight bend on one side as opposed to straight rails on both sides of the oil pan. I tried to find the engine serial number behind the distributor, but it apparently was ground off. Are there any other ways to ID what year my engine is? Physical clues or casting numbers?

The water pump and fan on a 55 and up 235 is different. However there is an adapter plate that converts the 55 up engine to use a 54 back waterpump.
Here is a picture of the adapter and waterpump on a 55 up 235 engine:
eBay item number 140366258216 These are sold by Chatter member pre68dave He has a information sheet with the eBay item.

Thanks MrMack. This brings up another question-- curious if there is a way to identify if I have a full-pressure engine visually-- both my valve cover and oil pan are off the engine now.

-Mike

I think if you have an oil disributor on the left side of the block its a splash engine. If you have that it would be just above the pan rail, and close to the center of the block.

If it uses the 1955 and up pan gasket it is a full prssure engine.

I want more input on this but my current observation on block year model is as follows:
Since you mentioned the oil pan being off, On the inside of the block in the crankshaft throw area, in each bank of two cylinders, and on the non oil pump pick-up side is cast a 2 digit number that may by coincidence be the year model of the block. I have a 54 261 that exterior casting bunbers shows to be 54-55. I have a later 261 block that I flipped to find a 56 which I believe is the correct year that it came from.
I am curious to see what others have to say on this method of year identification. fact or fiction?

Are the raised casting numbers on the passenger side of the block there, above the starter?

se are actually on the inside of the block so the oil pan needs to be removed to see them.

INSIDE ? ?

The casting numbers are on the right side of the block - behind the starter.

The casting date code for the block is located behind the starter.



The first letter stands for the month { A is January - L is December}
The second number is the day of the month
The third number is the year.

{My truck is coded H 7 7 = August 07 1957}

----------------------------------------------------------------------------

The 7 digit casting number is cast on the side of the block just ahead of the distributor hole.



{My truck 3837004 indicates 55-57 235 }

This chart will help decode most 235-261 engine block casting numbers...



Over the years.... I have found that the numbers that are stamped on the pad to the rear of the distrubutor do not provide much reliable info.



The block casting date {near the starter } & the block casting # {to the front of the distributor } are the best ways to ID a motor & they are easy to see if the motor isn't caked with years of grease.

Now that was a plateful of goood information.

Bob

The problem is the 1958 and up have the casting number behind the starter.

That is Incorrect ^


This picture clearly shows that the casting number is visible on the side of the block just to the front of the distributor hole on my 1959 261 motor.




Using the chart above....3769717 decodes to a 1959-1962.. 261 block.

I had a number of people that have found the casting number behind the starter on the later 235 and 261 engines.

Hmmm.... Interesting Chevy Nut

Do you have any pictures or documentation to back up this claim ?

Or is this one of those....
I know a guy who knows a guy who said......

This is from another chat site. A number of guys there have responeded that they could not find the casting numbers of their 235 and 261 engines.....until they removed the starter and there it was. Also many of the 261 engines have the so-called captains bars showing above the starter.
Try chevytalk.org and do a search in both the 1949-54 and 1955-57 forums.

Just as I thought.
Your claim remains unsubstantiated at this point Chevy NUT.

Not understanding why you want us to search the '49-'54 &'55-'57 archives over there when your claim only regards 1958 & up motors.



Please provide the links to this so called discussion over there Chevy NUT.
http://www.youtube.com/watch?v=TFu9LIjhs-4

The casting number on my " 61" 235 is behind the starter and is barely legible. John.

Here is a webshots album of 2 261 blocks that I have. The 54 is the one I want to build for my truck. The other is an old scab that I have had around for years. The 54 really puzzles me because the date code shows something other than 54. The casting number according to most sources can only be 54 or 55. I added the water pump mounting areas of both blocks to show the difference. I also showed the inner block casting numbers that I mentions. I have just about decided that I am wrong on the assumption that these are date stampings. The casting numbers are shown for both blocks also. I captioned all of the photos but didn't realize that you had to click on the icons to read them. Looking forward to all comments and input. Thanks, G.H.

You messin' with my brain Greg .... but there is some good info. here.
3733950 decodes to a 54/55 261 block
[img]http://rides.webshots.com/photo/2951982800047579877eozFck[/img]

And 3837012 decodes to a '55-'57 261 block
[img]http://rides.webshots.com/photo/2863015950047579877VNuAzO[/img]

So what do you make of that date code on the 54 block? I'm about to scratch a hole in my head.

[quote=Greg_H I'm about to scratch a hole in my head. [/quote]

Just for Shitz & giggles.....I suggest that you install your tin foil hat for protection & ask about this over on the StoveBolt site Greg.

Let us know how that works out for ya.

These numbers can be useful, but I am skeptical of the ones that are hand stamped (uneven) because....in states like Texas that used engine numbers to ID and title vehicles before 1955 it was customery to stamp the original engine number on the machined area which was left blank on a replacement engine or block. The installation mechanic (if in a Chevrolet dealer shop) would hand stamp the number on the block, in order that the vehicle kept the correct engine number. In other stated many reolacement blocks were never stamped. My 53 Belair 2 door sedan has an 1954 style truck replacement block(solid lifters) and 54 style water pump with a 1956 casting number. The machined engine number area ia blank. The car was a powerglide once and some previous owner converted it to a 3 speed standard(1954 transmission) The hole for the clutch peddle is cut with a torch. The trunk ornament has POWERGLIDE on it.

If you have engine numbers that appear to be factory stamped you can ID the engine as to year model from engine number charts, the prefix initials are good information to tell if an engine is a 1951 or 52 or if it was a standard or powerglide.

The 1954-55.1st style 261s continued as "Service" replacement engines for several years after 1955 and the block will show the casting date as the actual date that it was produced. Chevrolet sold them as replacements for the babbit rod 235 truck engines and even sold a 60 pound oil gauge for it.

When I refer to 1954-55.1st style 261s, I am talking about one that has the early 1941-54 style water pump and uses the early style pan gasket.

The casting date is what it is!