I have a '04 4.6 F150 with the 4R70E transmission. Transmission is gone. Since the truck has always been down on power since I've owned it, would switching to a 4R75W transmission work in it and increase torque. While the truck is down for repairs, what would be some options to power this thing up? I haven't ruled out an engine swap as Crown Vics are cheap.

 

The 4.6 2V engine is more reliable than the 5.4 3V due to the VCT. You didn't say how many miles were on it?
Might make more sense to repair the trans and sell it and buy or trade it for a 5.4 with 4R75W as new as you can afford.

 

Replacing a 4R70 with a 4R75 will make absolutely no difference in the way it runs.

 

It has 154k miles I've always complained about it being the slowest vehicle I've ever owed but for some weird reason I've owned it longer then anything I've ever had. I'd just like to have more acceleration it has a 355 gear.

 

Regear it - if you still have stock tire size go to 4.10's. Get a programmer with custom tunes.