doughboy4.6

How much power will it gain with this swap.

2000GT4.6

Not nearly enough to make it worth the cost unless you go all out.

Dark_Horse

if you are going form a PI 4.6 to a PI 5.4 probably 20 hp if you get an after market intake manifold. but you will have about 90 more ft-lbs more torque. i like my 5.4 i love the torque it makes...Awsome. but if i could do it again i would get a newer DOHC 4.6 it will make more power and easyer swap to put in