The Trick Flow heads have excellent flow at low lift which seems like a good idea but it can be too much of a good thing with a long duration cam. At low engine speeds you can blow the intake right out the exhaust since it flows so good. On a race engine you never notice it but on a street engine it will cause problems. For that truck I'd lean towards the small size for the cam. That truck probably isn't super heavy and I doubt that you want to go really fast in it so just focus on making 0 to 90 fun. 90 mph is probably 4500 rpm so no need to use a cam that has a powerband from 3500 to 6500. I doubt you want to see the high side of 6000 rpm in a truck like that.
