The 4.6 actually has more compression than a 5.4. 9.3 to 1 vs 9.0 to 1. The 5.4 block is taller and wider to accomodate the longer stroke. Cylinder pressures are nearly identical because they use the same heads and camshafts.
Most of the headgasket problems that I have read about are oil leaking out of the back of the head gasket. I believe this was on the 4.6's though.
Jimmy

 

Hmmm... with the same bore, and a higher displacement, isn't more force put on the head ?

I didn't mean static cylinder pressure, I should have elaborated...

 

"Most of the headgasket problems that I have read about are oil leaking out of the back of the head gasket. I believe this was on the 4.6's though.
Jimmy"

Perfect discription of the blown head gaskets on the my brothers' 5.4Ls, I have talked to mechanics that claim they have NEVER replaced a head gasket on a 4.6L and the ones that have said they have only done so with engines that have been "messed with" to try and get more power... ie Mustangs with teenage drivers/mechanics.

Must of the 5.4L problems I know of where related to F250s especially Super Duties. Just too much mass and wind resistance for the little engine to move around. Always seemd like you where pushing it hard even going down the road empty.

Actually the Ranger was an American truck with a German engine and a Jap transmission - don't ask me how they got all the combatants from WW2 to work together.

 

That's the exact reason I got the V10 - at least, that's what I told my boss when he leased it for me

As to the WWII combatants, that's probably the ONLY reason they are all working together...