Art Carr Servo clearance (same as Sonax?)

I have an Art Carr Servo that looks identical to the Sonax ones. The piston is tight in the bore and I think it may be causing my 2nd gear flare. Bore inside diameter is 3.501. Outside Diameter of the groove where the O-ring sits is 3.281" for .110" per side total for the nominal 1/8" diameter O-ring which measures .117" vertically and .128" horizontally (Its flattened out in the groove). How much should I turn down the groove?

It's in here, Frank tells how much to cut it.

http://www.460ford.com/forum/showthread.php?t=113120

Thanks. I had seen those where he says to cut .007" deeper or .014" off of the diameter, but then in another post he says you want to compress the O-ring .005". If I take out .007" I won't be compressing the O-ring at all because I'm compressing it .007" now (.117"-.110" = .007"). So I'm still a little confused. Do I take out .007" per side or just .002" to get to .005" compression?

take the .007 out and you'll be good to go.

Was a while ago but pretty sure i only cut .007 from the diameter and piston slid in nice , didn't need to go more .

just pm Frank, he will get you fixed up