What would you do??? I have a 90 yj with the 4.2, mc2150 an the GM dizzy. Trying to get the best bang for the buck. Should I do the 4.0 head swap? Iv heard its awesome and that its not worth it. Get a mild cam and new timing chain or a 4.0cam? Both? I like the carb setup. Fuel injection might get more pricey than i wanna get, an what all do i need to do it? What do ya think?