Chevy or GMC? what year? the makes and series are different - there was no frame number on Chevys until after 55, and then it's the same as the number on the door tag, except they left off the leading number and letter [which indicates the model], because when the frame was assembled they didn't know exactly which model it would be, the "real" vin/VIN/VSN of a Chev is the number on the door tag - that's the only ID you should need, the [changed] engine number is irrelevant .... GMC is a whole different animal
Bill
