You are using it for what it was designed to do so not a lot of expensive racing mods are needed. Likewise expensive hard to find speed equipment isn't needed. All of the stock components are plenty rugged for a truck engine. You may have to search the internet some but most parts are obtainable. Check with older machine shops and parts houses in your area. When I worked at CarQuest 20 years ago their computer system could search the inventory of every CQ store in the country, if you can find someone to search. O'reilly has a way for the counter person to get help from the home office in Missouri for hard to find parts. Best Gaskets makes a great new set of gaskets.
Ellis made 2x1 carb manifolds for all kinds of inline truck engines and they show up on eBay often. Duel carbs, long headers, more compression. and possibly a special low RPM cam, but the stock cam is fine for you. Possibly custom pistons? Quite a bit can be milled from both the head and block to raise compression.Just remember to be honest with yourself about what you want your truck to do. It can not haul 10 yards of wet dirt and do the 1/4 mile in 12 seconds.
