Hopefully this message won't post twice, my connection went down the first time I tried to send it so I'm resending.
I hadn't cut a groove since the new guideline came out about cutting in a 22.5-30% angle instead of flush with the throttle plate, so this was my first try at cutting the new angle. I actually felt like I butchered it as the bit bounced around a lot and had a lot of "chatter". Nevertheless, when we tested it, there was a lot of new power and the owner was very pleased. Now I have to see what happens with the mileage.
The walls on the throttle body were very thin. Using a midsize bit, I cut through into the idle air passage in 2 places and had to pull the idle air valve out to access and patch them.
