Hi Hot Rod, Brakes are not the problem, The emergency brake is in good shape and the bands is good. The truck will freely roll and I had spent time on a project to redo my brakes a few years back and the power brake unit was not very healthy then. I live on a 100+ acre farm and working on a project to get my sawmill in operation and need a few loads of fill before I call in some gravel trucks. I just built a 30 x 50 saw building and money is a little tight as I don't finance with them bankers

The truck has made this hill about only 100 feet many times before

The questions I think of that needs solving are:
Why is there more compression than the truck manual shows as designed.

I did not mention that I had a accelerator pump problem so I borrowed the plunger from my 65 c-10 230 6 cyl and it does pump but probably not as good as it should.
I failed to check for blockage in the carb siphon tube when I had it apart.
The truck may not be getting enough fuel on demand.

The vacuum is lower than it should be but I cannot locate any further vacuum leak.

Is there a trick to adding some choking to help provide more fuel air mixture
can I mix some hotter fuel with acetone as I am using non ethanol gas
Is there something that I am not seeing or thinking about as I am not a mechanic by trade.
I just need to enhance the power to get this truck to do what it did before.