The Stovebolt Site Forums The Shop Area General Truck Talk 1951 gmc pickup with a 248 motor

Hey, Guys I am learning aboout my dads old truckit is ecerything of a 1951 gmc pickup but the motor is a 248 with a A in front of the motor number which the motor number is (A 248 I 45293) I think after alll i have read is this motor had been replaced by gmc according to my mother the first motor went bad before warrenty went out and they as gmc put a 248 motor in the truck instead of a 235. this truckhas 8 leaf springs on each wheel. I need somebody to help me with this, i am getting ready to sand blast and prime this comming saturday.so if anybody can help me i would really appricate it. If it would help my e-mail address is ([email protected]) Thank you'll, Moonshine Mike

A is a notation of bearing set dimensions, there are a few different sizes A B C etc.

the 51 GMC, in fact any GMC, did not come with a 235, the GMC got a special line of high pressure oiling engines. you cant install a 235 where there was a 228/248/270 and vice versa, the GMC engines are about 5 inches longer which is why the radiator is tucked inside the core support.

the 248 is correct for 1951 GMC. if you have a 248 and 8 leaf springs, I would bet it is a 150 which is a 3/4 ton.

Is there any other way to tell if it is a 3/4 ton or a reg. p/u

can anybody tell me if the truck i have that has 8 leaf springs is a reg. p/u or a 3/4 ton .

whats the VIN number on the drivers door jamb plate?

also, the hood should say 100/150/200

A 3/4 ton will have 8 lug axles and single rear wheel, with an 8 ft long bed. the shifter will be on the floor and it will be a 4 spd. you can get a one ton single rear wheel, but I think a one ton will have more than 8 leafs.

the vin. # had been gone off the door, and all it had on the hood was a gmc emblem no numbersw of such , so i am trying to figure this one ot it has a short bed with 2 stakes on each side. Just trying to figure this one out.

The GMC engines were about 2" longer than the Chevrolet engines.

The truck would have come with a 228 originally. 248s came in 2 ton and larger trucks. Dealer replacement with a 248 under warranty is very possible.

If you have a 1951 short bed GMC frame, it would be a 1/2 ton model.


The "letter" preface in the Engine Serial Number was used to indicate a variety of possible combinations of "non-conformities" to "standard" engine specifications for cylinder bore and crankshaft journal/bearings specs:

"A" preface specified:
+ 0.005" cylinder diameter bore
- 0.010 main bearing journal diameter
- 0.010 rod bearing journal diameter

1951 GMC light truck standard spring-set leaves:

front springs: 8 on 1/2 & 3/4 ton, 7 on 1 ton
rear springs: 8 on 1/2 ton, 7 on 3/4 ton, 8 on 1 ton

1 ton, a GMC model 250, will have 137" wheelbase and if a pickup truck it has a 9' bed (4 stake pockets per side). The frame rails behind the cab are also flat on top.
A 3/4 ton has shorter bed and often slight hump in frame over rear axle.
Both have 8 lug wheels, and springs may have been changed or perhaps special ordered differently than expected.

1951 GMC Specifications , compliment of Rob English.