| Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Duramax might be too wide for '40's trucks, most of which were inline 6's. 5.9 Cummins might be too long except for COE models. 4bt might be best choice.
Modern driveline, front axle in particular might be too wide, GMC have rare wide front fenders, Stude have spacer strip that can be easily widened.
Troll through build's on here to get ideas.
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.
| 
