It is amazing how Ford is cheapening the Ecoboost for the F150. We got metal valve covers and intake, they get plastic. We have a niceer exhaust manifold, they have cast iron.....
Makes you wonder....
It's not necessarily "cheapening" as you put it, implying poorer quality. In fact, it's just the opposite because it has to pass Ford's Truck durability standards, which are MUCH more stringent than the car durability ones, therefore causing quality to increase, even though part cost might actually decrease.
-With the valve covers, Ford is now able to produce composite materials that outperform or match the performance of the metal ones, but with lower weight and heat retention.
-The intake got redesigned for more low end torque, as it's needed for towing in the F-150. As far as material goes, it's easier to get a smoother surface out of a composite part straight from the mold over having to machine or sand a metal part after casting, meaning better airflow and less cost.
-Finally the cast iron exhaust manifolds are much more durable than the sheetmetal based ones in the SHO, mainly because they are one piece and not two layers welded together. Why do you think they have been used on trucks for decades? The SHO simply couldn't package the cast ones and the F-150 has enough room to allow them.
All in all, if the parts perform at least as good as the parts they are replacing from the SHO to the F-150, why not use them because it means the customer is getting it at a lower cost. From what we heard at the EcoBoost presentation at the Convention, the F-150 will have increased boost and performance over the SHO as well, so if those parts hold up under higher stresses, I don't see the problem.
Sorry if this seems like a bit of a rant, but some people still see composite/plastic parts and assume they are inferior to metal ones, when that is usually not the case. Look at Carbon Fiber as an example. Some composites might not look as pretty as carbon fiber, but than can outperform their counterparts.