Pull timing?

With the Camaro, we used to kill a few tenths by changing the launch rpm and adding tire pressure so the slicks slipped a little. It worked great for the 6.0 index class (1/8 mile) we used to run. The car would go 5.70s in good air.

We use a little trick and move the linkage up one hole on the carburetor. Went from 9.83 to 10.11 and didn't skip a beat.

How much rpm did You lose on the top end to lose 0.4 sec?

A lot of guys I know use a stop under the gas pedal. Others use a plate under the carb, like a T/S but not electrically controlled. Doing these things can affect reaction time which might be a good thing with no box???

Weight. Timing. Shift points. I wouldn't get excessive with retarding the timing. 3 speed footbrake? Try leaving in second gear and see what it does. Maybe a mechanical stop like a Moroso 65042 or 65040 if you can find one. You may be surprised how much you have to do to kill that much. Try unhooking the secondaries once to see what that does.

I like the second gear idea!

I use a mech throttle stop plus I lower the launch
rpm and the shift rpm to drop 1 full second.. the
mech throttle stop is set at about 1/3 throttle then
the lower rpms.. slows me from 8.96 to 10.00.... in your
case I would believe the lower launch rpm and shift rpm
would be good enough

Some great ideas! Thanks!

Philly cheese steaks

This is what I would use EZ PLATE

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.

I went to T&T last year to see if I could slow my D50 down for the 7.0 index. I was running in the low 6.30's that night. I usually shift at 6800. I tried shifting at 5600 and it would only slow down to a 6.50. I need full throttle to leave on a Pro Tree (4 tenths).

If you can you can, slide the throttle cable housing
forward to give you less throttle... it takes a lt
more than you think

1/2 second is a lot of time to kill with shift points, weight,or timing. the only way that I know of to kill that much time is a throttle stop. The best way to go is a plate style like: Dedenbear or #1 stop. I use a #1 stop. If I am racing in a no electronic class I take the air cylinder off and replace it with a spring. All of the other good index racers that I know of, do it the same way. If you will only ever race non electronic, you can use an ET Genie or an Easy Plate.

I have been using the Moroso mechanical stop p/n 65042 ( modified with a longer threaded rod) for over 8 years now and have been very successful with it. I am slowing about 8-9 tenths on average. I use it to slow down to 11.50 for Street Eliminator and for 11.50 index racing. Electronic and air operated stops aren`t allowed in the classes I run. I considered a plate system, did some research and talked to racers using them and came to the conclusion that my system is best for my combo. I have seen some of my fellow competitors using weight and shift points to slow but again i feel my setup works better. A word of advice: if you use the Moroso setup be sure and use a throttle linkage bracket like one from Jegs etc. so a second bolt can be used to attach the stop as it will tend to move if used only using the carb bolt. As a matter of fact I am going this Saturday to a Test and Tune to get the stop dialed in for my new motor combination.

The old Moroso 65040 (discontinued) worked well. Maybe find one for sale somewhere or make a similar piece out of a throttle cable bracket mount

Cut your carb in half.

Drive the stripe, it's easy. Lol
Seriously if you are index racing detune the motor so it can't go more than. 25 under. Lower compression, thicker gasket, retard cam cl, smaller carb.