Engine ID Help

[Brett M]

A friend & I have been trying to ID a side valve six engine.
The engine # starts with P20
The length of the block is a bit over 25"
Any help to find the spec's for this engine would be great.
Thanks
Brett

[Andersun]

P20 218ci Plymouth Car Plymouth 6 De Luxe and Special De Luxe 1950

[Brett M]

I didn't think that the 218ci engine came in a block length measurement of 25 1/4 "
Brett

[Kaegi]

how long is the head? should be a 23 inch head on a P20. When people refer to 23 or 25 inch blocks they are measuring the head

[Brett M]

Kaegi,
I measured the Block & also the head both at 25 1/4".
I have also found out that Canadian produced Plymouth engines are all made from the 25 1/4" blocks, the stroke of the engine was adjusted to get the desired CI. This was due to cost & tooling issues.
Regards
Brett

[Kaegi]

Kaegi,
I measured the Block & also the head both at 25 1/4".
I have also found out that Canadian produced Plymouth engines are all made from the 25 1/4" blocks, the stroke of the engine was adjusted to get the desired CI. This was due to cost & tooling issues.
Regards
Brett

Brett, you are correct about Canadian. ALL Canadian mopar 6 cylinder flatheads are the 25 inch block. they never sold the 23 inch there. I think because the market was smaller there was no point in tooling up to make both. I don't know where to access Canadian engine block numbers.