Seems I read that boring to 0.020" is good, but not to exceed a 0.040" bore; 413 to 440 would exceed that bore model, yup. Gary H. -----Original Message----- >I can't >bore a 413 to a 440 piston. I can go to 426, but cylinder walls would be >thinner than I would be comfortable with. ---- Please address private mail -- mail of interest to only one person -- directly to that person. I.e., send parts/car transactions and negotiations as well as other personal messages only to the intended recipient, not to the Clubhouse public address. This practice will protect your privacy, reduce the total volume of mail and fine tune the content signal to Mopar topic. Thanks! '62 to '65 Mopar Clubhouse Discussion Guidelines: http://www.1962to1965mopar.ornocar.org/mletiq.html.