Originally Posted by snrusnak
I know, I said "LOL" see^^^
I think the heads are different in 2008 so the cams won't work, but I'm not positive. Realistically, it would probably be more cost effective to swap the newer 4.7L complete with ecm into the truck, then modify it from there, if you are wanting to drastically increase output. The older 4.7L is a good engine, but wasn't a big hp producer. There are many differences between it and the new motor. They are similar motors, but they change a lot just enough to make it hard to "upgrade" to the new engine. Basically it's the same platform, but they changed all the parts enough that you can't swap them back and forth lol.
I think these are the main upgrades to the newer engine:
Crank girdle instead of individual main caps, I think some of the rotating assembly is a different/lighter/stronger material(rods/pistons), cylinder heads are different, different ports and combustion chambers, not sure if valves changed, but they changed to two plugs per cylinder as well(new heads supposedly flow much better), different cams, intake and exhaust manifolds changed, TB made larger and now is fly by wire, entire exhaust was upgraded I believe (bigger diameter)....my dads 05 is much smaller than my 2010, different tuning, hybrid electric/mech cooling fans supposedly lessens the drag from the mech fan = more hp freed up...
The guy at airram built his 4.7L up a lot(intake,exhaust,tune,heads,cams,etc...) and I don't think he even reached 300 rwhp. I should be close to 300 rwhp with just tuner, intake, exhaust with the newer 4.7L.
I'm not trying to discourage you away from the older 4.7L just trying to give some info...