What Can Be Dome With a Chrysler 400?

With 4.11 gears it will have plenty of low end if the engine is in any kind of tune. There are better intakes for sure and if the cam is large you might benefit from changing it. We are probably going to need a little more info to realy make any reccomendations. Like intended use of the car, is gas millage important at all, what holyy carb, what compression ratio,and it wouldl realy help to find out exactly what cam is in the car also what the torque converter is. The 400 is a good performer short stroke means it will like to rev and big bore helps breathing it will be very similar to a 383 just a bigger bore, also can be stroked for some serious displacment.