Originally posted by brucer:
A 1,000 RPM bump is non trivial. Traditional weak spots are piston rings and the valve train. The trade-off on piston rings is thick/heavy for long life, thin/light for high RPM's. I suspect the rocker/followers/hydraulic lash adjusters are limiters on these engines, based on the change to direct bucket followers on the heads in the Jags (according to T. Haines).
Stock valvetrain is capable of 8k rpm's without failure. Tested for several seasons.
Stock piston rings as well and these same rings were used on the 450+ HP Duttwieller turbo engine.
The weak point IMO is the rods and bearings at high rpms and/or boost... Still with that said several folks with 7500rpm S/C Duratec's that have no problems with reliability. Not including the S/C that is...
