The flat part where the distributor is mounted is the deck; it was used to stamp the particulars concerning the original vehicle where this engine was originally installed. This information makes a difference in obtaining parts because most cars had hydraulic lifters and trucks had solids.
The characters you are looking for are stamped (about 1/4 inch high) and usually have a letter followed by three numbers and ending with another letter (or two). The first letter is almost always F because most GM engines were made in Flint, Michigan. The following numbers represent the month followed by the day of the month. The final letters denote the vehicle in which the engine was originally installed.
Serial Numbers
A stamped serial number appears on the flat part of the distributor deck. The first letter is either F for Flint, Michigan, or T for Tonawanda, New York. These were the two locations where engines were manufactured at the time. The numbers following the F or T designate the calendar month and the date the engine was produced. The remaining letters are in accordance with the type and series of the vehicle. This helps to tie the vehicle together with the engine. Regular production orders (RPOs) were standard orders that could include many variables, and Chevrolet had several of them that were popular with dealers. (The appendix includes the car and truck listings for 1954–1962.)
Head Casting Numbers
The head also has important casting numbers. In my research, I found very little information for heads manufactured between 1954 and 1962, but I found the three most popular. The head casting number is located outside the valve cover in plain sight on the driver’s side. If you have heard that the new-style 235 gets better compression numbers with an “848” head and that’s important to you, look for those as the last three numbers of that casting number.
Without removing the valve cover, the head’s casting number is clearly stamped just before the carburetor. The rest of the head’s information can be obtained by removing the cover. This is one of those infamous high-compression 848s.
Here are the head casting numbers that I can verify, so this is a short list:
• 3835913 1954–1955 235 engine
• 3836848 1956–1962 235 engine
• 3836850 1956–1962 261 engine
The acorn nuts have a rubber grommet under them with a metal washer. Notice the slits in the valve cover that allowed underhood road grime into the engine. It’s best to close those up and use a vented cap.
With the casting information, you should be able to decipher everything General Motors recorded about your engine. This is invaluable in determining what engine parts you need for your rebuild.
Visual Differences
You see a few telltale differences when perusing listings of engines during the purchase or selection process. These differences help you determine the correct Stovebolt era in which the engine was made.
Deciphering Engine Numbers for This Project
Below the distributor is the casting number, 3764476. This engine was built between 1959 and 1962. Just above the starter is CON3 (the third conveyor at the factory) and B 28 9. The first letter corresponds to its month, A through L (A for January, L for December). B is February, 28 is the day of the month, and 9 is the year. We now know this engine was built on February 28, 1959.
Now let’s look at the serial number that is stamped on the flat part of the distributor deck. That number is F302B. The “F” means that the engine was made in Flint, Michigan. The “3” indicates the third month, March. The “02” signifies the day of month. The “B” stands for the model/series of the car engine with Powerglide (hydraulic lifters).
So, March 2, 1959, is the date! When you stop to think about it, the line must have been busy at the time because the serial number only lagged the casting of the engine by two to three days.
The head follows a similar numbering scheme. On the driver’s side on the outside, not covered by the valve cover, is the casting number; in this case 3836848. It indicates that the head was made between 1955 and 1962 and was used on cars and trucks. Just inside the valve cover in almost the same location is another clue: CON9 (the ninth conveyor at the factory), and about four springs to the right of that is another number H 3 0, which is the date that the head was made, August 3, 1960.
So, this probably isn’t the head that originally came with the engine, unless the engine sat on a shelf for about 18 months. When you see a casting number ending in 848, you know you have the highest-compression head Chevrolet made for that engine. ■
The year 1953 was a transition for Chevrolet. In early 1953, cars were equipped with the older-style engine; in the latter part of the year, some were equipped with the newer style as the factory ran out of old parts. The factory did not start everything new at the beginning of a year. So, some 1953 cars had the new engine, some did not. As far as I can tell, all 1953 trucks came with the old-style engine. This is why I use pre- and post-1953 to describe these engines. ■
The coil was mounted in the center of the engine until late 1953. At that time, Chevrolet located the coil between cylinders number-4 and number-5. This is a 1950 216. You know it’s an earlier engine by the long side cover, short cap distributor, and acorn nuts holding down the valve cover from the top.
Notice the space between the center of the harmonic balancer and the center of the fan. It is considerably more than the post-1953 engines. Prior to 1953 all the engines had 5/8-inch-wide belt pulleys.
Pre-1954 216/235 Engines with Babbit Bearings
• Two acorn nuts on the top of the valve cover holding on the valve cover
• A side cover that extends from above the spark plugs, all the way down to the oil pan
• A water pump arrangement that centers the fan on the radiator (this is on the vehicles that the engine came with due to a taller radiator)
• A short cap distributor
• A horn mount on the intake manifold
1954–1962 Engines with Modern Insert Bearings
• Four screws at the base of the valve cover to hold it down
• A short side cover
• A lower-set water pump
• A tall-cap distributor
There are other much-less-noticeable differences, such as carb style, generator, and starter differences, but these are the best identifiers of the era of the engine.
The short cap distributor cannot use a tall cap because the internal shaft is too short. This prohibits installing HEI, but other than that, the distributors are interchangeable.
Post-1953 intake manifolds have the knob sticking out for mounting the horn, just no holes drilled.