It's a 1955 235 block casting number, had been pulled from a '50 COE. So it wasn't the original engine to that truck. 11" clutch disk matches flywheel 11" friction area. Little longer snout on flip side of disc as shown this pic. No markings that I can see.
Matthew 6:33
1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com
