Have a F250 Superduty that has a totally blown barely limps along 5.4. Needs total rebuild plus machine work.... Cant afford it now. So I have a running 4.6 short block with heads that I can put in the truck just to make it run and drive under its own power.

Anyways in the next year I want to build a higher-than-stock-performance-engine. Which I dont know alot about and I just started working again so it will take some time to gather the money.

So just wanted to know if one over the other is a better block and heads to start building from? If the 4.6 was for some reason better than a 5.4 to punch out, rebuild and put performance parts in.

If the 4.6 for whatever reason was better I would keep that out of the truck and go get a 5.4 that another friend just happen to get in a F150HD (7lug truck) that was rolled. He got that after I got the 4.6 unfortunately. I could get it for only a couple hundred dollars.

Bottom line is I am going to put a runner in my truck right now so I can drive it and not trailer/pull it with a chain everywhere. Just want to know if one engine was better than another to start a build on.

 

I have a built 4.6L in my truck, so I can't complain about having the smaller motor. That being said, if I could snap my fingers and it would turn into the 5.4, I think I would be crazy not to do it. I think your toughest decision will be who you get to build it. I have never built a modular motor, but I hear they can be finicky if you haven't built them before. That's why I bit the bullet, and had a professional race shop build mine.

 

Rebuilt the 5.4. It will work better with more torque for such a large truck. If it was an F-150 or Expedition then I might side for the 4.6 for cost saving stand point.

 

The 4.6 and 5.4 are about the same money to build.
For power, the 5.4 is the better motor and there is more options for positive displacement supercharger set ups for the 5.4
Nether one can be bored out much at all. ):

 

There is also an option for a positive displacement supercharger on a 5.4 4 valve as well.