340 bore tolerance question

I've known a few builders that want a little bit of taper so that as the piston travels up and down the rings essentially open and close, helps to clean them (at least that's the theory) but race engines want 0 taper. What that taper tolerance is for a 340 is not known to me but I wouldn't go more than .003". I'm sure one the other guys will chime in with the tolerance. We are talking taper ie. smaller at the bottom than at the top of the bore and not barreling right.

Terry