No serial number stamped on block - HELP!

[Ranger]

The engine block in my 36 plymouth has no cast number. The pad on the engine is smooth and has a tin plate screwed to it. The number stamped on the pad is P115929BC. I can't find any reference to this type of tag or this number to identify where the engine came from in any books or one line. Any help identifying the history of the engine would be appreciated.

[Don Coatney]

P-11 is a 1941 Plymouth. Perhaps the engine in your car was replaced with a newer engine.

[Ranger]

Thanks, I was told it had been replaced years ago by the original owner. Good to know the year. I won't sound so dumb at the parts counter now.

[greg g]

Well I'm not sure you can be 100% confident in that assumption.  What number does your cars ownership documents use for Identification?  Some agencies used engine numbers and some use serial numbers.  Chrysler sold unnumbered blocks to rebuilders.  Some were competent shops and restamped or riveted on as in your case the original engine number into the rebuilt block to satisfy the numbers on the ownership documents. Some didn't and left it blank.  But that said you can not assume that the block is an actual P11 block  Depending on when it was replaced is could be a 218 or a 230.   Look around the block and see if you can see any cast on numbers that look like a date.  But you would would need to know the bore to determine the cu inch.  You can measure the stroke by removing the pipe plug in the head over #6 cylinder and inserting a long piece of stiff wire.  This will ride up and down the piston as you turn the engine over by hand.  This will allow you to measure the stroke.  4 3/8 = 201 or 218 depending on bore and 4 5/8 = 230.