First timer seeking wisdom

[spinning wheels]

Double hump heads were a good design back in the late 60's, early 70's. The motors with these heads were installed in chevy's lighter cars. Most (not all) of these cars also had high compression pistons, solid cams and heavy duty valve springs, 1.94" or 2.02" intake valves.
Then again, back then you could buy 100 octane gasoline at your local gas station. Today there are better designed heads available that can run on the lower octane fuel. it all depends on where you want to make your power. Most hi-po heads, will make more hp in the higher rpm range. Not sure if that is were you want to make your useable hp and torque, when the motor is going to be used in a daily driver truck.

One thing to consider, is what you are going to be using your truck for.
For example. A friend of mine had a very clean 68 LWB, he installed a nice running SBC with a 700r4, with disk brakes up front. As nice as this truck was, he wished he had gotten a 3/4 ton truck, because he was towing race cars and project cars, more often than he had planned for. He liked the bigger brakes on the 3/4 ton trucks vs the 1/2 ton. He ended up selling the truck for little over 6K. He was able to get that kind of money back in the late 90's. Not sure if he would have gotten that in today's economy.

It also comes down to, how much money you are willing to spend on the truck. Or, how much mechanical abilities you have.
I swapped my 3/4 ton truck, for an '88 Ford Ranger I had, with cracked heads. Then again, the GMC had been sitting in a back yard for 6 years and had plants growing thru the suspension. I needed a tow truck to drag it out. I have since done a lot of work on the truck, and the truck still looks like a beater.

Ok, I'm stepping off the soap box..... Hope this info helps in your decision.