Math
AKA, I change the low gear ratio and rear end ratio in my old NHRA legal M.W. 1963 415 HP Stocker, took out the 4.89 rear gear with the stock 2.45 727 low gear ratio = 11.98 SLR to a 4.56 rear gear and swapped the trans to a Mopar 2.77 low gear ratio which made SLR 12.63 ratio.
Those two changes made that car a lot quicker and faster
I was running that car in B/SA at that time and it had to weigh 3520 with me in it, NHRA had lower the HP factor on the 1963 low compression motors 405 HP due to them having a smaller set of carbs and a smaller camshaft than the 1964 M.W. low compression motors had
Test, test and test some more to learn and hopefully go faster and quicker

3.28 in trans 5.57 in Dana 18.27 SLR 9 X 29.5 tire Shift in the air.

Need a little more info, like size of engine, weight of car, size of the rear tires.



Joe

What are you using to calculate SLR ?

We changed the SLR in this car from 9.17 to 7.77 , literally no change in the ET . But now it barely picks the tires up

I have a stock geared 727 in my cuda and I use 295 drag radials. Motor makes somewhere around 850 hp, plus 300 hp of nitrous.
With a 4.10 rear gear, the SLR was 10.0 and it was uncontrollable on nitrous. I rarely ever got it to hook, but when it did, it just did wheelstands. I had a couple of "good" passes where it went fast, but the vast majority of runs were aborted.
I swapped in a 3.54 gear for an 8.67 SLR and it made a HUGE difference. It has hooked almost every pass since. The only time it didn't hook, I had the front shocks set too loose.

The drop in SLR hasn't seemed to affect the ET much so far...on the nitrous anyway. I'm still tuning this thing, so getting it to hook and repeat has been priority.
With the tight 4k nitrous converter and 3.54s it still ran 9.69 at almost 142 mph on motor only, super sluggish 1.43 sixty foot.
Best NA pass w/ loose 5k converter and 4.10s was 9.54 at 140.4 mph, 1.32 sixty foot. The car would usually hook anywhere the track was at least halfway decent w/ the NA setup.
At my car's weight (over 3800 lbs), I really need a different trans.

COUGH....Glide with 1.58.....COUGH

COUGH....Glide with 1.58.....COUGH

Who's making a transbrake for Torqueflites that will use second gear?

. Dont get hung up on an "ideal" SLR number as it is VERY combination dependent.

I think you need to work on the shock settings(maybe valving)and concentrate on the wheelspeed side of things more than worrying about the SLR. . Here is a video of 11.3:1 SLR that builds wheelspeed right now, and what most here would consider to muchbut if you can control wheelspeed it will always be the fast way down the track with a bias slick. We run the same tire you do a 29.5x10.5, we have been 1.13 60' with no wheelie at all, but if I wanted to i can just about flip the car over with a twist of a couple screws. If we are talking radial tires its a different animal but I assume when you list your tire size its a bias tire. And in that case wheelspeed is the key...Oh yeah excuse the make of the car its what we race these days

We pull zero timing, in fact we ADD timing in first and second gear in the Vette. I did in the Savoy because the tires are 7 years old and track temp was 155, and its a bracket car which is a different animal.I used those two examples to show why dont get hung up on a "magic" SLR number, there is not one every car is unique. Wanna really throw a wrench in the works our dragster is 7.38:1 and has been 1.03 60'(dont pull timing there even with a torque monster of an engine, good shocks control the housing and tire)

IMO ramping timing in on an NA deal is a crutch at best to cover up a poor working chassis or chassis issue. Make the chassis work and leave the timing alone, unless you have some huge torque monster on an engine like some we run with in NA 10.5, they go up to 700"+ or maybe a leaf spring car as I don't have much experience there so wont comment. NA engines generally don't recover very well when you pull timing in them and in some cases can be a significant amount of power lost. if and when I can get new tires on the tank I don't plan to be pulling timing for sure.

We had AFCO's on the Vette for a very long time up front. But the car basically has no front end travel, at most its 1/2" of travel. The travel simply is not needed in this case we let the ladder bars do the work. The single biggest gain we have seen was going to a shock built specifically for this car and its intended purpose. Our shock guy is Adam Drzayich and the shocks are custom Penskes. FWIW the Vette is 100% factory Chebbie stuff, sans the shocks obviously. Stock A Arms, stock steering box, stock steering with the addition of a steering stabilizer for the bumpsteer the stock front gets us.

in the end it is a give and take. The only way to find what works for you is try different stuff. IMO learn to make the car work with full timing. Ultimately adding it in low and second gear will make the car faster. It will help burn the excess fuel off from being on the chip at the hit and will benefit in second gear from the multiplication of the gear set. Get it back to base in high gear. But if you have a box that cannot make that happen for sure quit pulling timing. Learn to make the car work with all the power. Video is your friend for sure as well as info, Not sure if you have any data logging capability but alot can be learned there.

Guess i could ad the Savoy has an SLR of 10.4:1 and seems to work ok. Dont get hung up on an "ideal" SLR number as it is VERY combination dependent. Savoy ran a string of 1.33 60's a couple weeks ago at 7000' plus DA ar 3530lbs in Vegas pulling 12 degrees ramped in over 1.25 since we cant get new tires, well the ones we want anyway.

Safe to assume you have a Glide in the 64?

Joels on Joy Proflite...FWIW the Vette has an A1 Proflite in it.