What rear gears should I run?

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vegaracer
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What rear gears should I run?

#1 Post by vegaracer » Wed Apr 16, 2008 5:48 pm

Wondering what rear gears we should run in my car. Swapped over to a 434 from a 350 this winter. Have 4.88's in it now, and don't know whether to go to 4.33 or 4.56. Its going to be naturally aspirated, 1/4 mile racing. It felt last year like it was running out of gear. Just wondering what everyone's opinion is on this.
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1973 Vega
434 SBC, N.A.
Powerglide
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Bob West
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#2 Post by Bob West » Wed Apr 16, 2008 7:57 pm

4.10's, light car shouldnt need that much gear.
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79 Camaro
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#3 Post by 79 Camaro » Wed Apr 16, 2008 8:29 pm

Can you give us a little more info about your combo?

Where does it make power (RPM)?
What trans are you running?
What size slick?
What do you think the MPH will be in the 1/4 mile?
What converter are you running (stall)?
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vegaracer
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#4 Post by vegaracer » Thu Apr 17, 2008 9:36 am

I don't know exactly where its maximum power is. It should be around 7000 rpm. We're running a powerglide with a 5500 rpm stall speed. The slicks are right around 32" tall (maybe a little shorter). Hope to run right around 155 mph, but 150 to 155 would be ideal.
Feenstra's Towing

1973 Vega
434 SBC, N.A.
Powerglide
9.01 @ 146

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79 Camaro
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#5 Post by 79 Camaro » Thu Apr 17, 2008 10:14 am

vegaracer wrote:I don't know exactly where its maximum power is. It should be around 7000 rpm. We're running a powerglide with a 5500 rpm stall speed. The slicks are right around 32" tall (maybe a little shorter). Hope to run right around 155 mph, but 150 to 155 would be ideal.

Here is a link to the TCI racing Calc.
http://www.tciauto.com/Products/TechInf ... lators.asp

I plugged in your numbers with a 7% Converter slip and it came out to a 4.01 gear, so Bob was close :wink: , a 3.90 to a 4.10 gear would probably be ideal. Also being how your car probably aint that heavy, it shouldnt need a real stiff gear to get the car moving.

Oh, and what first gear do you have in the Powerglide?

Hope this helps??

Adam
"THE THROTTLE IS THE DEVIL" By Mr. Willis
"ALL I SEEN WAS HOOD!" By Mr. Heard
MAKO RS-1979
Sponsored By:
Total Removal Contracting-Tim Rogers

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vegaracer
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#6 Post by vegaracer » Thu Apr 17, 2008 11:02 am

I figured it probably was going to be around that. We have the 4.33's so we're going to try them.
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1973 Vega
434 SBC, N.A.
Powerglide
9.01 @ 146

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#7 Post by John_Heard » Fri Apr 18, 2008 6:05 am

http://www.dewcoperformance.com/ makes some nice gears :twisted:

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