Gearing Question

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Bruce69Camaro
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Location: PA

Gearing Question

#1 Post by Bruce69Camaro » Wed Nov 10, 2010 6:09 am

My co-woker is tubbing out his Stang.

His old setup was 434sbf, C-4, approx- 1000hp w/ 300 shot, 5000 stall, 28" tires, 3:73 gears shifting at 7200rpm.

His times were 8.94 @ 154mph.

His new tires are going to be 32" x 14" x 15" Hossiers.

He was told 4.56 gears. The program I use said 4.63's but then I thought, does this program take in consideration
for NOS?

Any thoughts on what the new gearing would be using the same drivetrain components?

Thanks

Bruce
Those who think they know it all have no way of finding out they don't......... :scratch:

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supernova
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Re: Gearing Question

#2 Post by supernova » Wed Nov 10, 2010 8:12 am

If it can handle the high rpm at the end of the track, I think more gear is better. Although I have 3.70's in my car it also has 28" tall tires.
Blackhoodmafia!!!! :mrgreen: :mrgreen:

1972 Nova SS
572 C.I. BBC

Best to date: 1/8
et: 5.28
mph: 134
new wt. 3340 lbs

mytmouz
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Re: Gearing Question

#3 Post by mytmouz » Wed Nov 10, 2010 8:43 am

I ran 4:30's with my 32's in the 1/4 on NOS, shift point was about the same...
Trucks are for haulin...

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Bruce69Camaro
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Re: Gearing Question

#4 Post by Bruce69Camaro » Wed Nov 10, 2010 8:53 am

The formula I used was: tire dia x RPM/ (336 x MPH)

Is this a good formula to use?

After I changed some numbers I came up with 4.49, which is close to the 4.30's.

Bruce
Those who think they know it all have no way of finding out they don't......... :scratch:

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wikd69
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Re: Gearing Question

#5 Post by wikd69 » Thu Nov 11, 2010 10:04 am

His old setup was 434sbf, C-4, approx- 1000hp w/ 300 shot, 5000 stall, 28" tires, 3:73 gears shifting at 7200rpm.

His times were 8.94 @ 154mph.

His new tires are going to be 32" x 14" x 15" Hossiers.

******

I used the above numbers and hit the Mark Williams (http://www.markwilliams.com/calculators.aspx) website - it's what I use for my gear / topend calcs, and came up with the following.

Using 154 mph as the target, here's what the calc came up with, for both the old and the new combo (mytmouz hit it on the head):

Image
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

mytmouz
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Re: Gearing Question

#6 Post by mytmouz » Fri Nov 12, 2010 9:04 am

Image
Trucks are for haulin...

Image

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