I didn't know wartime 270's had 4 bolt flywheels, 6 bolt, 11 or 12" clutch flywheels are sort of rare, make sure you don't find one for a 14" clutch, or could drill new clutch mounting holes, if it has the correct starter ring gear. Probably all angines after the war are 6 bolt flywheels, don't know for sure, however. Later flywheels will fit. Some have redrilled V-8 flywheels.

270 and 302 pans have lumps in the sides for each rod because of the longer stroke engines, I'm sure your 270 does, might check.

'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.