thanks guys. So if I see things right, I can thin down the guides, leave the short sides alone, clean up the rest and they ought to work fine with my .580 lift cam. I assume, that due to time at max lift there just isn't much to be gained concerning flow numbers above about .550, and being a street type motor no increase in port volume other than absolutely needed. These are going on a 380 cube 5.7 block motor.