if you bore the block then moly are far and away the best. if you are using rings in an old cylinder just ring ridge removed and deglazed sometimes called honing but it is not) then cast iron rings really shine here as they can sck up the irregularities and will seat in well lasting a long long time. if you use moly in a used cylinder like i just described they will in most cases never seat or sael and you will always have a slight oil burnerans puffer. I know you asked about in a frec sh bored cyl but i thought i would say it all and then folks cans ave it for future reference Now someone is going to ask "when do you use Chrome rings ?" The answer in one word for our motors. NEVER!!!!!!! Don Blood pressure low? Not awake yet? read Dons rants and get you self going again http://seniordragster.bravehost.com/OLDTECHNOLGY.html [Non-text portions of this message have been removed] ---- 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.