I have an 03 f150 with a 4.6 and i want to swap the heads out for some factory 5.4 heads and i want to know what all i would need to make this happen. Can i still run with the same 4.6 ECM? Estimates on how much this might cost at the engine shop etc.... I heard you can get some VERY respectable gains from this combo! Slap some dynatech long tube headers on there and i'll be pretty happy! i REALLY think ford dropped the ball by not making the 5.4 available with the 5 speed...could you imagine!?

 

Um. Don't 5.4s and 4.6s have the same heads? Or am I mistaken?

 

I think the heads are compatible (swappable)but they are different heads from what i read. i could be wrong. Any more info to clarify?

 

4.6 and 5.4 heads are the same. There are some differences between romeo and windsor, which you can tell by the 8th number in the vin: X=windsor and W=romeo. Romeo have 11 valve cover bolts on both sides, bolt on cams and 6 bolt crank, and Windsor have 13 valve cover bolts on the driver side, 14 on the passenger side, press on cams and an 8 bolt crank. As well as those differences in 2001 on trucks, 99 in mustang gts, ford introduced the PI or power improved heads and blocks. The difference is the block is equipped with dished instead of flat pistons and the heads have a much smaller dish, making the combustion chamber and the compression the same as the earlier non-pi motors. You swapping heads with a 5.4 will accomplish absolutely nothing. Unless your heads are bad.

The gains you're talking about come from putting a PI head, with the smaller dish where the valves are on a non-PI (NPI) block with the flat pistons. This makes the combustion chamber considerably smaller which raises compression from 9.0:1 to somewhere between 10.2:1 and 10.5:1. This gains around 30 rwhp, but pretty much puts supercharging out of the question due to the high compression.

 

my 4.6L has 5.4L W heads, there was a crack in one and the only whole set we found was for a 5.4L windsor set
its a dawg on take off. yes he's right about the SC option, but power is not improved with 5.4L heads
first hand experience

 

5.4 did come with the 5 speed but rare

 

Your looking at $700-$1200 for a shop to swap heads plus gaskets.Just put p/i heads on mine in the fall $1000 But your 4.6 has the same heads as 5.4. 99 and newer already had p/i installed from factory I'd just put the entire 5.4 in it you'll have to put alot off performance parts on that 4.6 to make the power the 5.4 has stock

 

I have seen that I have a W for the eighth number in my vin. ---(Romeo)---
My question is which one is better? I figure the bolt in cam would be much better but it seems like the 6 bolt crank is a weakness. I guess im just confused with this hole deal.

 

Yeah the 4.6 is incredibly over complicated. A 6 bolt crank is technically weaker but unless you're planning on throwing 500+ horsepower at it it wont matter. I have a 6 bolt crank in my f150 and have no problems.The only reason the bolt on cam is better is that it's a lot easier to swap out cams because you can do it with the AFM cam retention tool and don't have to remove the front cover.