[jhwalker]

Tom
I posted a note for car #2794 earlier, this post is from my own experience.
I have gone back and reread the entire thread.
My car is an older SPF #2117, but it also has a Roush 427R.

The first time that I tried to brake with the clutch in and low rpm I discovered that the engine did not make sufficient vacuum at low rpm for the brakes to be effective. It scared the poop out of me. It was the same issue that you described earlier regarding the 8" of vacuum.

The next day I took it to my installer and ask them to install a "vacuum assuring device". It was cheaper than changing the engine, plus I like the 427R, and I like the low rpm lumpy sound.

I'm no mechanic, but I know the vacuum pump runs when I turn on the car power and creates vacuum until some specified level is reached, and maintains that vacuum level.

I have never had a problem since I added the vacuum pump or cannister (or whatever it is called). I just spent two days at a track day at Willow Springs and killed a set of tires. I know my brakes are different, but what we have in common is the same is the 427R that makes no vacuum at low rpm.

Since most of the people whom I know who have a Roush 427R have addressed the low RPM lack of vacuum in some way or another, I have suggested to SPF that the dealers remind all buyers that if the engine installed does not make vacuum, NO vacuum-assisted brakes will work.

Keep us posted on how things work out.
JamesW