4.6 to 5.4 converson questions

since you have a cobra the 5.4 is a direct swap, save for a couple accessories on the front. your CPU and harness are fine. but unless going high rpm high compress whats the point? 5.4 costs a lot more to build to get the power then a 4.6... why.... why uses a 5.4? nobody, thus most parts are custom. its easily doable, just have cash handy or dont expect much of a gain.

Torinalth

the issue is the heads. if you have SOHC heads off a F150 then you have the problem of lost power. with the 5.4 you need at least 3v but preferably 4v to make the desired power. because the bock designs, the 4v and 2v are not interchangable on the 5.4 without a good deal of work, and of course the front cover and chains/guides... anyhow...

if its for bragging rights, sure go for it, just be prepared to spend some mad chedder. if you just want the power, you can do the same for cheaper on the 4.6.

Torinalth

4.6 to 5.4

I got a F-150 with a 4.6 and a expedition with a 5.4 and it seems driving both that the expedition has a lot more power or it could just be tourque

dont forget gearing as well. there are a ton of factors, its not just power. the 5.4 does have more torque, however the rotating weight robs a fair amount of high end poewr . something to remember is that the 5.4 is just an overstroked 4.6... no more bore, thats bad for the ratio. oh and if you are looking ot go stroker on the 5.4 that means even more stroke. this is bad for 2 major reasons. the rods will need to be billitt if you want to go more then 6krpm because the forces will be astounding, and 2 going with a stroker teh pistons will be comming out of the cylinder way too far... you have a recipe for a lot of problems if one thing goes wrong.

anyhow. trust me you can make some power, handfull of people have proven it... but thousands have proven it can be done with a 4.6, its cheaper and easier. i wont stop you if you want the 5.4, but go 4v navigator motor, forge it at least, if not billitt rods, full ported heads, and just remember you need a cobra R, sullivan, or custom intake. adapter plates for the use of 99 cobra intake is crap, not nearly enough volume to feed the 5.4. shrug, i decided against the 5.4 myself after doing all the research. going turbo when i do the motor.

Torinalth