Start simple. Tire pressure good?Brakes aren’t dragging? Tuneup (plugs, cap, rotor, fuel filter, and plug wires if needed) done? These are easy places to recoup performance and economy. Factory carb? If yes, good. If not, I’d make that my first stop. Do you know the gearing? He may have put shorter gears in it since it was intended as a towing rig. I know my dad did the opposite when he didn’t need to as much or as heavy loads. The truck has always done 98% highway driving, and there was a noticeable improvement in economy. You can check the SPID/RPO sticker in the glovebox, and it’ll tell you what it came with. That year should have each code elaborated, but if not, the code should be GU*. The gearing on that SM465 is not the best in terms of economy, but it’s such a good gearbox, that I wouldn’t run to throw it away just yet. You’re in AL so I’d throw away some emissions junk. If it has a smog pump, that can go. If it still has a cat or cats, it/they can go, and you can also consider switching to headers. Nothing else under there is going to rob you of anything. If it has a thermal fan clutch, great. If it has anything else, especially a flex fan, chunk it and do a thermal clutch. I would try everything I could on the outside before I started getting really serious with heads, cam, intake, and gearbox. It sounds like the NV4500 has caught your eye, but I’d try everything else before investing the time and money. I like your town, by the way. I’ve got an old high school roommate at UAH, and I actually used to live a few hours from there in Columbus, MS so I was there quite a few times for school and what not.
