What type of index racing? What are the rules?
Throttle stops on a timer are the best bet if allowed
MSD Grid with programmable timing retards if allowed
If no electronic aids allowed, retard the cam and use weight
4-5 tenth's is a lot to kill and be consistent
95% of what I race is on an index
Actually slowing 4 or 5 tenths with a typical .90 type timed stop where you leave at WOT, is a lot harder to do and be consistent than it is to kill a second and a half with that set up. Has to do with stop ratios and keeping it predictable. Basically you would just be blipping the throttle. Much harder to do and be consistent than if it's on the stop for maybe 2 seconds.
