Raphie,
Belive it or not, there are hyrdaulic lifters under the Cams. There are also rocker arms of sorts. The Cams do not directly contact the valves, but are driven thru a cam follower and lifter of sorts.
Not like an F-car or L-car where the cam lobes directly drive the valves.
On the Cobra R 5.4l engine (as well as the GT 5.4L I suspect). the part of the valve train originally came from a Dodge Neon 4cyl engine.
Ford really did grab parts from all over the place.
Im sure they are different from the original R engine, but I can't imagine how much .
I'll poke around and see if have some info on the cam geometry. There was a discussion by 4Cam and Boss330 on SvtP regarding the heritage of the Cobra R/ GT 5.4l engine, and what and where the parts originally came from.
In any event, Im told it is nothing to worry about. The early Terminator 4.6L engines had problems with cooling on the back sides of the heads, and had issues with head gaskets, but the 5.4L GT heads have enlarged cooling passages so it should not be an issue.
"Cut and Pasted from Bos330 Posting on SvtP...."
Lash adjusters YR3V 6C501 AA ZZ
(Forget getting these from Ford.. They don't exist. They however are under the valve covers of 3 million DOHC Dodge Neons. And.. the parts from Chrysler were updated around 2003 and are actually a better part than the oem Ford stuff."