Craig; Once you have Picked the cam your going to run then choose the Intake manifold. You have to make sure that the RPM ranges all match for the best performance, then you have to make sure the bottom end is in line with the rpm's you want to turn. It doesn't make any sence to buy a 8000 rpm cam when the bottom end is going to come apart at 6000 rpm's Do you know what I mean. The performer is good from idle to 5500rpm's and the rpm performer is good from 1500rpm's to 6500rpm's So you guy's need to decide if he wants to use this truck for towing or racing. The cam you choose should be with in the rpm range of the intake you choose. And the bottom of that 390 will come apart after about 6000rpm's so your better off with the performer Intake. Unless you plan on sticking thousands of dollers in the bottom end of the motor and oiling system. Hope this helps you out.


Vegas