A v6 Curiosity

I vote 3.9 v6 for an easy swap. Its based on the LA motor so you can bolt up any small block trans (including a 4 speed). I would probably use the entire drivetrain package and electronics, fuel system out of a 92-95 dodge dakota. They are simple and should be easy to trim the harness down since there was no security etc. The trans will fit (or at least in a b-body) since i have a nv3500 out of a dakota in my car now. You will have to make your own mounts for everything to use that trans but it was pretty easy.

If I do another swap in the future it will be a 3.9 v6 with a turbo charger. These things were used in circle track racing...there are some parts out there available and if you don't want to use the fuel injection, they were available in carb form in the late 80's.

Now if you go late late model engine, the pentastar 3.6 is a hot rod on its own. My 2013 Avenger pushes me back in the seat and well I showed a pontiac G8 my tail lights the other morning...

For a pentastar swap you would need a complete wrecked charger or challenger with the 3.6 and soon you can look for a ram too. (see what trans the ram is using, i bet there is a manual rear drive option) But if you use that engine you will want to use the ENTIRE electrial system including the security and just use the key since there is no after market support yet.

The 3.5 seems like a lackluster idea. for the trouble you get very little over the 3.9 and the 3.9 has a lot more options for hotrodding since it was available for so many years in the dakota. (people make cams, rocker, lifters, etc etc. and you can port the heads, increase compression...make the thing well over the 3.5 power output with way more torque.