These are stamped in block below left (driver’s) cylinder head. Car is 70’ Swinger 340. FW 340P37690336. X. If someone can decipher, please let me know. Thanks!

FW 340P37690336;

F - Series (model year) 1970

W - Engine assembled at the Windsor plant

340 - 340 CID

P - Premium fuel recommended.

3769 - Final assembly date from the 10,000 day calendar - Nov. 22, 1969 (1970 model year)

0336 - 336th engine assembled on the plant above on the date above.

Thanks much!....Any idea what the X means at the right of the #’s group? Joe

The the X on the TSB page shown at https://www.hamtramck-historical.com/images/TSBs/1970/D70-25-1%20page6.jpg

Thank you, It appears my engine was built with oversize valve guides in the cylinder heads............kinda' weird............Still need to get it up in the air to check V.I.N. near the pan rail..........I believe it is the original engine........... Definitely looks to have never been out of the car........car sat for a LONG time.......camshaft has been changed..........other than that it appears to have never been touched from the build date at Windsor...........headers were bolted on at some point.........under chassis type........