I wouldn't spend the money on the port job. Camming is more important at the lower rpms you're talking about, where flow rates aren't the issue.
If you want to rework the motor, I would probably: change out the rod and main bushings; ridge ream the bores and measure them, and depending on where they're at put .010" or .020" over rings in them; knurl the piston skirts; put in new valve seals and maybe guides; grind and lap the valves and seats; new valve springs; new lifters; a 12-235-2 Comp Cam; shorten the tires to 31x10.5 on 8x15 rims; correct the speedometer. I did that way back in the day with a 100,000 mile engine and ran it another 150,000 miles with no problems. The head work takes a couple hours for somebody with the right equipment -- no big deal as far as $$$. Money was a big deal for me then, and I got out cheap this way.
You could also go headers, decent mufflers, and a dual-plane intake. Do that and you're pushing 400 ft lbs and 300 hp at low enough rpms to enjoy it.
You'd get the same results with the base GM crate with the Comp 12-235-2 cam, headers, decent mufflers, and a dual-plane intake if you don't want to do the work.
Of course, if you're looking at crate engines, with a little more money.... LOTS of options!