The RPM2 is pretty good because of it's good runner taper in the torque dept but the explorer is still going to better just off idle. Really you should run the stock 5.0 truck intake because not only does it have excellent taper it's dual plane. You probably have plenty of bonnet clearance to run it but will require a 2 into 1 MAF tube which is also not difficult. They have the added bonus of being almost free to buy.