Best single modification,to your Mopar....

Gears, first went with 3.21--was OK but then a few years later 3.91 went in, that was more like it. Really woke the car up.

Now the 3.91 gears seem so-so, I know 4.30 or 4.56 would wake the 340 up more but then its already turning 4 grand on the freeways, lol

(I'm surprise nobody else said it, used to be the number 1 bolt on, then came headers and after that a hotter cam)