Are the internals forged like the 03/04 Cobra motor? I searched online but surprisingly there is very little information on this motor except for the wikipedia which doesn't go into detail.

 

Yes, the internals of the STR 4.2 S/C are forged, making it a formidable motor, capable of supporting 600+ chp. The Cobra's Eaton M112 blower produced 8 lbs. boost (13 lbs. for the STR's Eaton M112 blower), came with a forged crank, Manley rods and pistons, along with 6 bolt splayed main caps (remains a hot rod built engine which continues to exceed most newer metal).

 

Very cool... does it have variable valve timing or is that only on the NA 4.2 and 3.9 (in the Lincoln LS)? Definitely going to run a 3lb pulley and low temp thermostat. The only thing is you can't make the fan come on sooner to compliment the low temp thermostat, works great on my Mark VIII.

 

The 06 STR's came with VCT. Ya have to screw around to get the fan to come on early.

 

The 06 Technical Guide says the 06STR has VVT. It's to meet LEV/ULEV II emissions. It may also have changed torque characteristics somewhat but I don't recall seeing any before & after tq graphs!

Also got TPMS and SAI (aka AIR aka SAIR), revised EVAP, cats & various other stuff.

There's quite a bit of engine technical stuff in the 03 Technical Guide.

(TGs are on TOPIx.)