Re: Engine numbers

Posted by HH56 On 2023/3/16 16:39:45

A quick add to Don't post because I think he has a typo or extra word in the last sentence. If it DOES NOT have the bosses and holes in the lower block for the side motor mounts it is definitely pre 51. Without the motor number it is hard to say exactly what year the engine is because the only easily visible date is usually on the head and those can be swapped at will.

A not so easily visible date is low on the block so you might look at the date when the block was cast. It is located low on the block either below the starter or in a similar location on the passenger side. Can be on either end of block. Anything made before say early 1950 will most likely be a 23rd series or earlier. Anything later than mid 50 will probably be a 51 engine.

While the pre 51 models usually had the motor number stamped near the distributor there have been reports that Packard could have started using the rear pad on that particular block with 50 models. Some owners report their 23rd series 288/327 blocks had the numbers stamped on the pad above the starter.

You almost need to have the motor number to know exactly what year and size engine you have and whether there were any options. The hydraulic lifter option became more popular in the 23rd series and those engines generally had an H stamped as a suffix to the engine number. Other changes or options had different letters and a few even had a star designating some other change from original published specs.

If you do not already have it downloaded, the Engine Serial Number Reference has the numbers, what they mean and where to find them.