Forgive me if I repeat anything others have said, but I don't want to read through two pages of posts.
Although a 283 has the same talent as a 302 for rpm capability, and should be able to spin 8000 rpm without any mechanical modifications, such a configuration would probably run poorly in a truck, just because having to cam something for 8000 rpm with solid lifters would mean having no torque below 4000 rpm, where most of your driving is done. Or all of your driving, most likely.
So best to build the 283 on the torquey side. Get a nice hydraulic cam that builds decent torque, and maybe plan for a 6000 rpm redline. Any higher than that, and you probably wouldn't like it. I'd go with a cam that is no bigger than 220 degrees @ 0.050" lift on the intake. I'd get a dual pattern cam with more duration on the exhaust because V8 conversions are notorious for having to have iron exhaust manifolds because the engine bay is so dang narrow.
Finally, definitely plan on a taller rear end ratio. I've got a 4.56 in my truck, and I don't need to launch like a funny car. I know it sounds like fun, but it's not really, in fact it's unstreetable like that. Zip, zip, zip, and you're still topped out at only 70 mph. Plus you shift as soon as you get into gear. Oh sure, Porsche Cayennes have nothing on me, but I'd gladly trade some of that gear ratio for slower acceleration that just feels healthy, instead of always trying to jump out of its skin.
