Have a 41 plymouth but the PO put a newer motor in it. It is a 25"head with 869847-2 on the head and c28-42377 on the block. I believe it is a 251 but im not sure. Can't find any numbers that can tell me the size and what it might have came out of..???????
Check here: http://www430.pair.com/p15d24/mopar_forum/forumdisplay.php?f=2 It's a Chrysler, probably mid 30's. Good luck.