Engine SN is on right side behind distributor, stamped on machined pad. Starts with displacement, I e 248xxxx. Do not try turning engine over BEFORE removing valve cover, oiling valve stems and tapping them gently with a rubber hammer or 2 x 4. If stuck, tap gently while keeping them oiled ‘til they come loose. Otherwise bent pushrods may happen.

Ed

'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.