valuable hints, important info, or outstanding products that professionals have discovered after years of work. These will add to your understanding of the process, and help you get the most power, economy, and reliability from your engine.
CHAPTER 1
ENGINE IDENTIFICATION
Whether you are looking to purchase a Stovebolt for your project or already have one, the most important first step is identifying everything you can about the engine. This will serve you well when ordering parts and perusing parts at swap meets. Again, the desirable years are 1954–1962 with the 1958–1962 being the most desirable because of all the lessons learned by Chevrolet through the years. I encourage you to hold out for those years and purchase the newer engines wherever possible; however, there is more to an engine than its birth date.
Casting Numbers
The first place to start when researching information on an engine is a list of GM casting numbers in the appendix. It is an accumulation of data that has been updated over the years, so you should have no problem finding your Stovebolt in the list.
On the distributor side of the engine there is a treasure trove of information about the engine. Casting numbers appear just below and to the right of the distributor on the passenger’s side. They are notoriously hard to read, and people sometimes mistake a 3 for an 8. Clean the area thoroughly and use a bright flashlight. This is usually a seven-digit number and each letter/number is about 1/2 inch tall. A little engine degreaser and a wire brush often makes reading the casting number easier.
You may find road grime and buildup that fills in the numbers. You can use a good engine degreaser on a shop towel to clean around these numbers. It’s worth the trouble. Be sure to write down these numbers. Later, when you need parts, you will be glad you did.
Under the hood, the distributor’s vacuum advance can often obstruct the view. It’s easier to confirm this number from underneath the vehicle. This is the engine’s main casting number.
Here, “CON3” indicates the conveyor number that the engine came from. The numbers beside it are important for the exact date that the engine was manufactured. Also, of interest here are the captains bars above the starter. Most of the time, with few exceptions, this indicates that the engine is a 261.
The next numbers you need are the ones just below the starter on the passenger’s side: the conveyor number. Beside that is a usually four-digit letter/number combination separated with spaces like this: X XX X. For example, the first X is a letter from A through L (A for January through L for December). The center two digits represent the day of the month. The final digit represents the year that the engine was made within the years represented by the casting numbers below and to the right of the distributor.
The next set of helpful numbers are on the flat part of the distributor deck. This machined area has serial numbers stamped into it. If you have looked very carefully and found no numbers, chances are that your block is classified as a replacement block and has no numbers stamped on that deck.
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.
