For my´54 GMC-100 truck I need a replacement for my original 248 engine (frost damage). As far as I know this specific engine was built only in 1953 and 54 and is different to the Chevy engines. Is that true? Truck has a Hydramatic trans. I appreciate any information about if any other engine than this 53/54 GMC engine will fit to the Hydramatic or where to find a suitable engine or block. What is your advice?
Thanks for your help.
Frank

The GMC 248 engine was produced from 1941 through 1954. The GMC 270 and GMC 302 engines through 1962 will interchange and fit your truck and should bolt up to your Hydramatic (with the proper flywheel) if you wish to retain it.

The 270 or 302 will provide more power and can be modified to produce substantial torque and horsepower. The 248 and 270 cylinder heads will interchange; the 302 head requires a 302 piston.

God's Peace to you.

d
Inliner #1450

The difference between a 248 and a 270 is stroke. A 248 has a 3 13/16" stroke and a 270 has a 4" stroke. The rods are the same length so the 270 block is taller. They both have a 3 23/32 bore. A 302 has a 4" stroke and a 4" bore.
270s and 302s are the hot rod choice but a 248 is a good engine and can be built to perform very well. They usually cost less. Bill Fisher sometimes used 248 cranks in builds to reduce piston speed, smooth out the engine and even increase rpms.