I had a set of 906's done locally by a guy that races Mopars.

When the 440 was all together I just took it easy on it to break it in its a streeter first.

While driving the car to the Nats back then I noticed it was using a quart of oil every time I hit the gas station. Got home and the plugs were oiling down had to change them "often"

Broke out the Vaccum Gauge and at idle in the driveway the needle would "paintbrush" so fast over a wide range it was a total blurrrrrrrrrr.

Needless to say the Mopar Guru didnt replace the guides he just knurled them. Not sure how this procedure should have held up but in this case it didnt hold up it just sucked major oil into the cylinders.

After that I sent out for a set of 906's from a better place. With a stock 6 pack cam, six pack set up, HP manifolds and full exhaust at 4000 pounds went 12.95 at 104.9 mph

Im sure it would not have ran a 14 with them bad heads.....................