Also take into consideration that if you're adjusting timing on a cold engine you may not hear any pining until it gets to temp or driving around town.
20 does seem a bit high for stock unless you have cams with the lift/duration to match. In the past I used to adjust timing on a hot running engine by ear first to the PIng limit then see what my gun says. Then back it off by two or three degrees.
I'd then keep my ears acutely open when driving around town for a week or so to see if I need to do any further adjustments. You can also check your plugs. If you're getting a white or off white dusting, you are too far advanced and need to dial it back a couple of degrees.
08 S197 GT Auto: FRPP Strut Tower Brace, FRPP Bullitt CAI, Bama 91-P Tune, VBX remaned valve body with Superior Transmission Shift Kit.
Pending upgrades: Shaftmasters Aluminum 3.5" DS, FRPP 3.73 gears, Axle back exahust (?)
Originally Posted by LostBoyz
if you are getting 29mpg in your 5.0, you aren't driving it correctly