OldSub,

Thanks for the info, last night I was honing in on what you have just stated.

I wonder if I were to switch the front axel out with an axel from a newer K20 if I could also switch the rear axel out from the same newer K20.

My hope is to get the truck to a gearing that would allow it to be driven around 70 miles an hour without keeping the RPMs too high.
Not to mention fuel economy would be a consideration.

Unfortunately I have no knowledge on gear ratios to know what would accomplish these goals.
I have been spending all of my free time trying to learn from the internet.
But so far I am as dumb as I sound.

Thank you for your help so far any more information you can provide me is greatly appreciated.

Father daughter project is a 1964 3/4 4x4 stepside longbed.