Nick - Just a note that I think this topic better fits in the
General Truck Talk (GTT) forum so it's been moved there for further conversation and help.
When I get some time later today or tomorrow I'll dig through my GMC books to see if I can locate dimension details on similar year frames to see if there may be any correlation with your numbers and description.
In the meantime, maybe some folks with GMC info will chime in?
