I run the 295-65 radials at 19-20 psi for best traction. I've run the 275-60s and had good luck with them at around 18 psi, but never tried them any higher...didn't use them but a couple times at the track. I normally street drive with around 25 psi in them. CHIP

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax