Oldsmobile cutlass supreme 1980, cant go over 15mph
- Thread starter mickeypowa
- Start date
68-76 350 Olds block had the casting number 395558. I wouldn't worry too much about it as it's a 350 Olds block. If you really cared to find out the year it was made, there's a little machined pad with numbers stamped on it driver side front corner. This example shows it starts with a 3, which is an Olds car. Say, if it was in a Pontiac and a 403 Olds engine, it would start with a 2. The serial number depicts the car it came from, not the engine, whatever make that would be. The second digit is the last digit of the year, in this case it was a big block, so 1970. M was for Lansing, Michigan assembly plant, and the last 6 numbers should match the last six of the car's VIN it came from. There's also a chance, if it's an early block, it has the original oil fill tube and engine unit number stamped in it. If the unit number starts with say, a 1, it's a 1971, or a 0, it's a 1970, etc. In 1977, they went to windowed mains and got a separate casting number, and.....that's the year they started putting the engine size on the sides of the block, save for 260 that got a "355" for some stupid reason.
There's a 3 digit julian date cast in the block as the DAY of the year it was made. In this case below, it's 363. End of December. It's located near the distributor hole. Kinda hard to see if the engine is in the car. No year code, however. Just the day of the year. But again, all the 350 Olds blocks had the same casting number.
In the end, it matters not really. You have a 350 Olds engine in your car. End of the story.
There's a 3 digit julian date cast in the block as the DAY of the year it was made. In this case below, it's 363. End of December. It's located near the distributor hole. Kinda hard to see if the engine is in the car. No year code, however. Just the day of the year. But again, all the 350 Olds blocks had the same casting number.
In the end, it matters not really. You have a 350 Olds engine in your car. End of the story.
What is the big number on the head by #1 and #8 spark plug? It should be #8. As said, it IS a 68 to 76 block. I checked a 73 block with this big casting #, 39558-2. The Vin pan proved it was a 73 block. Glad he figured out those are the wrong spark plugs. My bet, it probably has something like 10 degrees base, about 10 degrees retarded, plugs not properly in the chamber and not getting anywhere near full throttle on that Holley carb swap.
