Same thing happened on my daughter’s 1996 GT many years ago.  Got the replacement with full aluminum water passages on ebay for about 1/4 the cost of one locally or from Ford.    No big deal to replace it since everything has o-ring type seals instead of gaskets.
Looks like alot more work than it was.

With plastic intakes................means a good reason.... 'to work on those ports a little'!!
Smooth those sharp internal corners Terry ........do the old hot-rod-thang!!!
Other than...being cheaper to make(and still charge the consumer the FULL load) plastic prolly isn't a big heat 'stink' like 'lumium.! My guess............
6sal6

Pretty sure they are molded in two parts then probably sonic welded together.  Internally they are usually pretty smooth, plus they only flow air as the injectors are basically in the ports of the heads.  They're convoluted and ,long to try and get low end torque out of a tiny engine.

terry wrote:

TKOPerformance wrote:

They're convoluted and ,long to try and get low end torque out of a tiny engine.

If you call a 4.6 a tiny engine what do you call those 2.3 eco-boosts that are cranking out 310 hp?/  itty bitty?? lol

No, not for a 4 cylinder.  I consider anything 2.0 and above decent sized for a 4 cylinder, but basically all those engines, at least any I'd consider a performance engine, use forced induction.  The issue the 4.6 has is that by V8 standards its tiny, I man, objectively its only 271 cubic inches.  Smaller than a 289.  Then to make matters worse its a cam engine (SOHC), which always need more RPM than a pushord engine to start making torque.  So Ford did all it could to try and bolster low speed torque, like using long intake runners.  What Ford really should have done was just build a bigger engine and stay with pushrods.  The LS and Hemi series engines sure don't seem to have low end torque issues. 

I just gotta see that slide rule next time I'm there.

In early 2000’s, Toyota’s 4.7L dohc made over 300 lb-ft and only 240 hp.  It was used in their trucks.

Nos681 wrote:

In early 2000’s, Toyota’s 4.7L dohc made over 300 lb-ft and only 240 hp. It was used in their trucks.

Yes, 300lbs/ft., but at 3,400RPM.  By contrast the 5.7 Chevy Vortec engine which was its contemporary made 330lbs/ft at only 2,800 RPM.  Which is a pretty clear illustration of what I'm talking about.  Its not to say that smaller engine can't make torque, or that cam engine's can't make torque; its just that they do it at a higher RPM which tends to make them feel soggy on the street, especially in a heavier vehicle.  One way to partially compensate for this is to use steeper gearing to get the engine in its powerband quicker off the line, but manufacturers often don't want to do that because then fuel economy takes a nosedive and they have issues meeting CAFE standards. 

MS wrote:

Hence my Hemi in my truck and my Durango. It cruises 80 MPH at 1850 RPM

Durango has 8 speed tranny
Ram 1500 has 6 speed.

It amazes me the engine has enough torque to power these heavy, not very aerodynamic vehicles at 80 mph under 2,000 rpm

They're a lot more aerodynamic than you may think.  Starting in the late '90s as CAFE standards became more stringent the OEMs really got into aero work.  A little rounding here and there that's super subtle makes a big difference in how that truck cuts through the air. 

The other major improvement was in electronic powertrain control.  Everything now is so seamless you don't ever know the engine is running on 6 or 4 cylinders out of 8.

Power also bumped considerably.  American V8s kept getting bigger.  Most of those Hemis now are 6.4s.