[Bnick166]

700 hp @ 7000rpm
3500#
32x14 tire
Turbo 400 w/ trans brake / 4500 stall
For 9" has 4.11s now (Locker)
Have spool w/ 4.86 street gear and spool w/4.30 pro gear.

[66bonne]

For the track ? I would first try he 4.11s. You're making a lot of power there with a lot of torque. A higher-numerical gear may be too much.
Good luck,
Jim

[BruceWilkie]

MPH= (RPM x TD) / (GR x 336) with manual transmission

With automatic use MPH= (RPM x TD / (GR x 355)

Use Wallace calculator to see @ MPH you should see at that weight and HP.

[S/st 54]

Hey Bnick! Hope you've been doin good!
My 2 cents is with that 4.30 you have might be worth a try. I'm sure uncle Tony put a good set of rods in that motor so crossing the finish line at 7100ish won't hurt one bit. I'm sure your power curve didn't fall off all that much so I bet your motor will like it! At 3500lbs it might like
The 4.86. I'd shoot to cross at 7300 if your motor peaked at 7k


Have you ran your car 1/4 mile yet with your current gear?

[BruceWilkie]

4.3 not worth trying imo. With a good convertor 7000 rpm works out to @147.
It's not going that fast with 700 HP at 3500 lbs.

If peak power IS at 7000, the shift point is likely around 7500. If the convertor is reasonably efficient the car goes thru somewhere above peak power and below shift point.
MPH @137 if 3500 is stage weight btw.

[AG]

Using 7400 engine rpm going across the line at 133 mph (assuming around 10.0 in the 1/4) with an 8% converter slip is 6800 rpm, a 4.87 gear ratio is required. If converter slip is less, it will take more gear, if converter slip is more, it will take less gear.

[Rob B]

I run close to the same HP on a 29.5 tire with a 4:10 gear @ 3420 race weight. I shift at 6000 and trap right at 6000. With a 32" tire, I would try the 4.86 to get the RPM range your shooting for based upon all the calculations given above and some real world experiences. And since you already have the set ups for both gears, start big and back down if you need to, at least that way you wouldn't be second guessing yourself on the gear selection.

[Bnick166]

Doin' just fine....life is good.
I haven't had it to the track w/ the 4.11's
I have a spool w/ 4.86's and I just ordered everything to go to the 35 spline pinion and a set of pro 4.30 gears. just wandering if I should give the 4.86's a try or just switch over to the 4.30's before I take it out.

Originally Posted by S/st 54

Hey Bnick! Hope you've been doin good!
My 2 cents is with that 4.30 you have might be worth a try. I'm sure uncle Tony put a good set of rods in that motor so crossing the finish line at 7100ish won't hurt one bit. I'm sure your power curve didn't fall off all that much so I bet your motor will like it! At 3500lbs it might like
The 4.86. I'd shoot to cross at 7300 if your motor peaked at 7k


Have you ran your car 1/4 mile yet with your current gear?

[S/st 54]

Originally Posted by Bnick166

Doin' just fine....life is good.
I haven't had it to the track w/ the 4.11's
I have a spool w/ 4.86's and I just ordered everything to go to the 35 spline pinion and a set of pro 4.30 gears. just wandering if I should give the 4.86's a try or just switch over to the 4.30's before I take it out.

Sure give the 4.86's a try...it will give ya some info that's for sure...dropping #'s down to the 4.11 would be a big enough swing to see what direction to go......also from what I hear Richmond pro gears aren't what they used to be. Give the guys from strange or moser a holler they can deffenently get ya pointed on the right path as far as parts.

Good Luck!!!!

[GTOGEORGE]

You know what’s funny is I have street gears in my car, they don’t make a pro gear in dana 3:73!


GTO George

[Bnick166]

I ordered everything from Mark Williams Ent.

[Bnick166]

You use a trans brake George?
I think that what creates carnage.

Originally Posted by GTOGEORGE

You know what’s funny is I have street gears in my car, they don’t make a pro gear in 3:73!


GTO George

[GTOGEORGE]

Originally Posted by Bnick166

You use a trans brake George?
I think that what creates carnage.

1,100 lbs of torque and a trans brake! Only broke it once since 1993!
Kinda funny huh!

GTO George

[Bnick166]

Maybe I'll give the 4.11's/Locker a shot w/o the trans brake....switch to the 4.86 spool w/o the trans brake and then swap in the 4.30 pro/spool and use the brake. Should give me info on what it likes.

[Half-Inch Stud]

Originally Posted by BruceWilkie

MPH= (RPM x TD) / (GR x 336) with manual transmission

With automatic use MPH= (RPM x TD / (GR x 355)

Use Wallace calculator to see @ MPH you should see at that weight and HP.

Both equations seem to work even while doing a burnout.