AM2 We were talking about replacing the 4.0 litre V6 and my opinion was that if they designed a V6 and a V8 to be produced off of the same tooling (pistons, valves, etc.) they could create two new and powerful engines for nearly the price of one. If you take the single piston displacement of the 4.0 V6 and multiply it by 8 the result is 5.3.
I see, so you mean make a new modular family made up of V6 and V8 engines...
I was wondering if the Duratec35 is the largest Duratec V6 Ford will produce, maybe they can still produce a larger 3.8 - 4.0 liter version for the Explorer and Mustang. ...sort of like Nissan's VQ family which starts from a compact 2.3 liter V6(replaces the old 2.0) all the way up to the large 4.0 liter V6 used by the Pathfinder SUV and Frontier pickup.
The 3.5 can be enlarged to 4 liters... it was designed for that. I believe we'll see one eventually... now that the 3.5 is finally in production (2 years late due to some engineering bugs). And, yes, the Mustang/Explorer/LR3 4 liter is horribly obsolete and needs to be abandoned. My site has a large section on the 3.5... including a pic of an intriguing rear wheel drive version that was shown to the public first.