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How much gear for the 1/8 mile
#188207
01/08/09 11:26 PM
01/08/09 11:26 PM
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Joined: Dec 2003
Posts: 576 Bend, Oregon
67cuda340
OP
super street
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OP
super street
Joined: Dec 2003
Posts: 576
Bend, Oregon
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I am wondering how much gear I should be running for the 1/8 mile. Currently I have 3.91's I shift from second to third at the 1/8 mile. 6000 rpm's. 8.3 at 85mph. The car is street driven/ not highway. 1973 Dodge Dart Sport 360 X heads solid cam 727 manual valve body 3500 stall drag radials 325/60/15's thanks for input. Matt
1973 Dodge Dart Sport 360 Drag radials
12.30 1/4 mile 7.82 1/8 mile
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Re: How much gear for the 1/8 mile
[Re: barracuda man]
#188210
01/09/09 12:01 AM
01/09/09 12:01 AM
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Joined: Dec 2003
Posts: 576 Bend, Oregon
67cuda340
OP
super street
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OP
super street
Joined: Dec 2003
Posts: 576
Bend, Oregon
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my 60 ft times are 1.9 thanks for the input.
1973 Dodge Dart Sport 360 Drag radials
12.30 1/4 mile 7.82 1/8 mile
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Re: How much gear for the 1/8 mile
[Re: 67cuda340]
#188213
01/09/09 10:14 AM
01/09/09 10:14 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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It all depends on how many revs you want to pull but 4.88 is a good over all gear for a SB. Figure your rpm's at the traps then figure the % of gear change you want.
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Re: How much gear for the 1/8 mile
[Re: 67cuda340]
#188214
01/09/09 11:00 AM
01/09/09 11:00 AM
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Joined: Jan 2003
Posts: 16,925 NC
440Jim
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,925
NC
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Quote:
I am wondering how much gear I should be running for the 1/8 mile. Currently I have 3.91's I shift from second to third at the 1/8 mile. 6000 rpm's. 8.3 at 85mph. The car is street driven/ not highway.
Matt, unless you have a spare rear end center section setup with the new gears to swap out for street vs track, don't gear the car for 1/8 mile when it is a street car. I wouldn't even gear it for 1/8 mile if it was a race car unless it was something special, race gear it for 1/4 mile so you don't have to say "I can't run 1/4 mile my car is geared for 1/8"
That being said, if the mph at the 1/8 mark is the same, the gear change in a 727 from 2nd to 3rd is 1.45. So to cross the line in 3rd at the same rpm and mph as 2nd:
3.91 x 1.45 = 5.67
Now if you pick up some mph, say from 85 to 90, then use:
5.67 x 85/90 = 5.35
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Re: How much gear for the 1/8 mile
[Re: 440Jim]
#188215
01/09/09 11:10 PM
01/09/09 11:10 PM
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Joined: Dec 2003
Posts: 576 Bend, Oregon
67cuda340
OP
super street
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OP
super street
Joined: Dec 2003
Posts: 576
Bend, Oregon
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Jim,
What you are saying makes sense. I really wont gain much if anything. thanks for the input.
Matt
1973 Dodge Dart Sport 360 Drag radials
12.30 1/4 mile 7.82 1/8 mile
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