Crane has a couple that might interest you.
p/n cra-210511
.467/.498 lift int/exh
248/360 adv. duration
192/204 duration @ .050
112 lobe seperation
rpm range 1000-4000
depending on what your after, they offer two more but the next one is as follows, the first would probably be ideal though.
p/n cra-213901
.498/.530 lift int/exh
260/270 adv. duration
204/216 duration @ .050
112 lobe seperation
rpm 1500-4500
