Ive got a 2003 F150 with a 4.2 in it. Im wanting to switch to a V8 possibly a 4.6, but i was wondering if they can be interchanged with out to many modifications. The truck is a 5 speed manual 4 wheel drive and i dont know if the bell housing will match up or if i will have to change the transmission also. i know most F150 are designed for the 4.6 so im thinken it cannt be to hard.