Offset valve spring retainers or keepers ?
The 256 voodoo or Howard works best with stock compression, gears, converter street
you can go to the 262 voodoo but you start to loose some driving across the intersection
The 268 comp sucks big time without converter and gears and a hot rod driving style
short duration and as much lift as you can find
but not a Whiplash if you value your gas mileage