The F150 is one helluva truck.
My all time best choice is alway's the 300cube straight six efi.
my Bronco presently has the 302 V8,,,still a nice motor,,but not half as good at pulling a trailer like the 300cube efi six was.
Your Silverado i couldnt advise you on,,,since i'm a Ford man when it comes to trucks. come to think about it,,,i'm a Ford man when it comes to cars as well. Lol