I have had a pair for over 25 years on several different combos, got them back in the 80s as I bought a complete 340 with them for $2400. Still have them on my 363 with well over 1,000 runs , it has the old ductile iron non roller rockers. never broke one and only replaced an adjuster or two. i bought a pair on here for my present 408 but my engine builder talked me into a complete Indy 360-1 top end so i sold them again on here. Still have the 363 as a backup motor ran great, good oil pressure etc. when i took it out ( it was 11.5 to 1 and I wanted to get away from race gas ) My 408 is pump gas.