Welcome aboard alex.
From what I can find in my sources, you should have a 228, not a 248. The 248 didn't come out until '53. Also, it seems that most GMC engines from that era were either a bright red (similar to IH red) or an olive green. I'm thinking that the engine may have been changed or overhauled by a p/o. The generator should be black, and most intakes I've seen were either unpainted or were the same color as the engine block.
I don't think that GM ever used a primer on their engines, and the only silver engines I know of were mainly Chrysler, Hudson, and Nash.
