I believe there is a 1/4" spacer that goes between the front of the generator mounting bracket ( the one under the generator that bolts to the block ), and the back of the generator end frame.

I'm helping a fellow bolter with a '48 truck that has a '58-'62 235 in it and is equipped with a 6-volt, long frame (10-1/2" overall length) generator. It has a generator mounting bracket of 6-1/8" overall length and requires a 1/4" spacer in front of the bracket and a 1/2" spacer in back of the bracket to match up to the generator end frames. This truck has 3/8" pulleys.

I also have a '38 truck with a '48 216 in it with a 12-volt generator with is also 10-1/2" overall length. It has a homemade generator mounting bracket of 6-1/8" length and matches the factory bracket on my friends '48 truck. It has the same set of spacers on it. This truck has 5/8" pulleys.

If the water pump pulley and the crank pulley are in line then you probably need the 1/4" spacer on the generator.

'38 Chevy 1-1/2 ton
'49 Chevy 1/2 ton
'54 Chevy 6400 2 ton
'55.2 GMC 3/4 ton
'56 GMC 1-ton

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