I did it to my SVT. Well, I built it into the intake pipe I made. I used the advice from the Duratech Performance forum. I started with a 1/4" hole and enlarged it one drill size at a time until I found a size I liked.
Def. pick a size on a moderate day. If you do it when its cold outside then when summper comes and your idling with the AC on and crank the steering wheel you might stall. If you do it on a hot summer day you'll moose and get hang when its cold outside.
I have 5/32. In the cold (below 50) it doesn't moose but it hangs a little. When its hot (over 80) and the engine is warmed up, idling, the AC kicks in and I turn the steering wheel the engine slows down, stammers for a second and catches back up.
Some of the hard core guys have a few different pieces with different sized holes that they change out at different times of the year. Smaller holes for the cold times and larger holes for when its warm.
