Most of those ‘73-up Fords and I believe all the Chevies had front disc brakes.
The rear drums were large. They stopped. Everyone didn’t crash into everything.
The tailgates were all 65” wide. Nice and standard. Everything fit.
Now they’re around 60”, and the interior box dimensions are narrower too.
And nine-foot stepsides sre gone. Those were great trucks. The huge strong solid step made it easy to reach in, and the lack of wheelwells inside the box made them easy to load and easy to sweep out.
The extra length was to make up for the loss of cargo space in relation to a fleet side.
As far as how much power a 454 makes.... you can get a LOT of reliable power from a 454. 400hp is easy to get. Throw on some modern Edelbrock aluminum heads, an intake, cam, and carb, and the truck won’t be slow.
Or just drop in a new crate engine from GM.
MPG you can’t get. But the savings over a $75,000 new diesel buys gas nearly forever.
The old trucks weren’t junk, and did have their strong points vs. today’s versions.
Let’s say you’re miles from nowhere and your truck quits running.
Would you rather be in a ‘77 Chevy or a ‘17 Ford? I can tell you which one you have a better chance of getting running.