1992 Dodge Dakota 5.2 Magnum advice

The first thing is to free up the exhaust.
Any other mod you do, will be choked by a single exhaust and the logs. Say you spend $300 on an installed cam, and move the power up 400 rpm which should make say 30 horsepower. But the logs and single exhaust choke half of them. Kindof a waste of time and money,right? If all 30 hp were available, your engine might feel 30/230 = plus 13% bigger..............at peak-power RPM say 5000, while giving up some off-the-line grunt. But if only half of them survive the exhaust system then it will only feel 15/230=plus 6.5% at peak-power.But I think I see a better solution;
You already have the 3.91s, that's great. But if you have a 727, the starter gear is 2.45 x 3.91 =9.58.Which with typical truck tires of 225/75-15 (28.3 tall), could be better. This combo will get you 42mph @5000 at the top of first gear, which is pretty good. But,that O/D will get you 65= 2100. So there is room for a bit more TM,Torque Multiplication. For example; 4.30s would cruise at 2300, yet the starter gear would be 4.3 x 2.45= 10.54. This would really launch the truck if you could make it stick. Top of first would now be 38mph, but more importantly, top of second would be revved out at 5000=64mph. And even more important, the downshift into first at 30 mph would be about 3950. The extra TM of the 4.30s will make your engine feel like it just grew by 4.30/3.91= plus 10%. And it will feel like that in every gear, and at all rpms. The only other mod to your 318 that will do this is supercharging. (or stroking,I guess,lol). And gears are cheap. And you can keep your single exhaust a little longer.
If you only need a little more oomph off the line, then a higher stall TC is the most logical solution. This will allow the engine to wind up several hundred rpm higher, to where more power is available. This will really wake up the combo. You'll need a traction aid of some kind.

Now if you combined both of those; a higher stall TC and gears, well, that is the most bang for the bucks spent.