Well after going throught the linked info I'm quite sure my 56 is a 55. The things that tipped the scales are that in 56 gmc didn't list a 248 as an engine. The other thing that might be the final straw was that in 56 gmc went to all 12 volt systems. If that is correct then my truck is a 55 as it was a 6 volt when I bought it in 75. Can anyone verify the 12 volt only in 56 for gmc? Also, if it is a 55 is the correct way to state it, 55 1/2 or 55 2nd? This is all a major shock after owning the truck for 36 years.
