8.8 gears please help

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dfwcobra

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Jun 2, 2008

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Jun 19, 2008

#1

• Jun 19, 2008

• #1

I have a 306 with 93 cobra heads ported, trickflow stage 2 cam and c4 tranny w/3200 stall and trans brake. Tires are 26x10.5x15. I will be running nos w/ carb plate maybe 150 shot. Question is what would be a good set of gears as far as ratio goes for a 1/8 mile track? Any help would be great. Thanks

 

wildstang90

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Nov 24, 2004

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Bristol, TN

Jun 19, 2008

#2

• Jun 19, 2008

• #2

I would say 4:10s if all you do is race the car.

 

rd

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Jan 12, 2000

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Ocean Springs MS

Jun 19, 2008

#3

• Jun 19, 2008

• #3

Best way to do this is to crunch the numbers. What rpm do you want to cross the finish line?

Give yourself a coupe hundred rpm cushion, and take that rpm back to see what gears you need, with your tire size to get that.

I have 410 gears, 275-50-15 BFG Drag Radials, and I cross the finish line at about 6000 in the quarter mile at 105 mph.

I set it up for eigth mile and I don't dare run much faster on a quarter. I have tried a 456 for eigth mile, but I cant run the quarter with it.

 

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Scorcher2005

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Apr 17, 2004

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Jun 19, 2008

#4

• Jun 19, 2008

• #4

Is this also a daily driver? If not does it see a lot of steet time? If so, I'd say a 3.55. 3.73 for a more strictly 1/4 mile car. 4.10+ if only an 1/8th mile car. I had 4.10s in my old AOD GT and didnt like them very much. Should have went with a 3.73. But i recommend the step lower to you just because of your power adder.

 

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dfwcobra

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Jun 2, 2008

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Jun 20, 2008

#5

• Jun 20, 2008

• #5

Track only. 1/4 mile trcks are too far so I won't be going to them. I was thinking of 410 or 433. Rpm wise I would say around 6100. Thanks for the input.

 

SVT32VDOHC

waiting for the next hack atta

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Nov 22, 2001

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Motor City

Jun 20, 2008

#6

• Jun 20, 2008

• #6

1/8 mile? 4.10's baby!! 1/4 mile I would go 3.73.

 

67coupe

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Apr 5, 2002

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Huntsville, AL

Jun 20, 2008

#7

• Jun 20, 2008

• #7

You said track only. What mph do you expect to run in the 1/8th.

With 26" tires and a trap rpm of 6100, here are some trap speeds I calculated (I have an excel spreadsheet for gear vs. speed).

3.73 @ 6100 = 126mph
4.10 @ 6100 = 115mph
4.30 @ 6100 = 110mph
4.56 @ 6100 = 103mph

Hope this helps.

 

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dfwcobra

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Jun 2, 2008

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Jun 21, 2008

#8

• Jun 21, 2008

• #8

Thanks for the help. Just ordered 433's.