1973 340, want more power.

Lustle said
Before you start throwing parts/money at a problem that doesn't exist. LEARN about your car. You don't even know what camshaft or rear gears you got. Basics. I know exactly how many miles my cam has on it. How many times the oil has been changed. I know my rear gears and how many miles are on them. I can probably even tell you how many fart's I've drilled into the seat.

KNOW everything about your car. Then you can know what to change. Can't know what's mismatched until you know whats in there. Otherwise it's like trying to bake a cake blindfolded and without the recipe.

Just to play devil's advocate...... If you haven't owned a car for a long time, and you don't have a lot mechanical skills, then IMHO it is too tall of an order to become all that familiar with your car before doing any mods. You might be years before doing anything.

To the point made earlier, about gears, the OP says he likes the present rear gears for cruising. So, my view would be to work with that as a starting point, and not insist that he change them to any particular numerical ratio. It may not be optimum on the strip, but I read the OP as being very happy with a decent high performance car. He should correct me if I am off-base there (please do so!).

BTW, OP to check your rear gear ratio:
1. Jack up the car's rear axle (place jack stands under it) and take it out of gear. Turn one rear wheel while watching the other; if the other turns in the opposite direction, you have an 'open' rear gear carrier (not a limited slip type). If the other wheel turns in the same direction, then you do have a limited slip rear diff (SureGrip for a Mopar).
2. For a limited slip rear axle, place a mark on the driveshaft and turn one wheel exactly 1 turn while watching the driveshaft mark. See exactly how many turns the driveshaft makes when turning the wheel exactly once. For a limited slip type, the number of turns on the driveshaft equals the gear ratio.
3. For an open rear axle, you need to block the other wheel so it does not turn. Then rotate the wheel near to you exactly two turns, and count the number of driveshaft rotations. That will be your rear gear ratio.

Do this as precisely as you can. You should get a number like 3.23, 3.55 or 3.91, etc. Here is an article on this procedure: What Gear Ratio is My Rearend?