The 283 is a classic engine, and period-correct for the truck, but your driving habits are going to have to undergo a pretty dramatic reset. 283's like lots of RPM, and the HP advantage it has over the 235 is going to show up somewhere north of 3,000 RPM. Torque- - - -from a 283- - - -forget about it!
If you're planning on building a weekend cruiser that seldom if ever carries a load, the 283 V8 is a good option. If you plan on doing truck stuff with a V8, adding another 1/2" of stroke in the form of a 350 transplant would be a better choice, and the 350 can be dressed up as a 283 in disguise with a little tinkering so only a purist would notice the difference.
Jerry