I know it's 2 years gone by, but I can't let this go without saying...
The 5.0 explorer motor is a BEAST!!!
I hear the "gt40" version is good, but i'm talking about the "gt40-P" version. the cam that comes in it is LAME; it makes the stock 5.0 HO mustang cam look radical, and that one is done for by 5000 prm. but it's roller-cammed, so you change it out to an emmissions-legal Ford racing E303 cam,, and a set of roller rockers, plus a mild valvespring/retainer kit. Finish with headers, cai, pulleys, and a 65 or 70mm throttle, and you've got 300 HP, 330 peak torque, and - most importantly - a broad torque curve that is above 300 all the way from 3500 to 5500 rpm, and good pull well past 6000.
it was also emissions legal with longtubes and high-glow cats, got better gas mileage than stock, and had excellent drivability - advantages of a broad torque curve. it takes aftermarket headers, pullies, rockers, and cam - BUT , for a 5.0 those parts are cheap and plentiful, and with the "p" heads and 1.7 rollered E303,, it's a torque monster!