Ive been running a hughes solid flat tappet for 8 years now, using their cool face light weight lifters, ive gone 9.79 at 139 with it shifting at 7000 crossing about 7300 in a small block, it has lived so far,use the right oil and you shouldn't have a problem, I change springs once a year just for peace of mind, ive considered going roller but I don't want to have to grind my rocker arms for the bigger springs, plus the bigger springs take horse power to compress,