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Discussion Starter · #1 ·
For those that changed from 4.10's to 4.30's,
what did you actually gain at the track???

I'm seriously considering swapping out my 4.10's for 4.30's (or maybe even 4.56's),
and would like to here from anyone who's actually made the change.
(Please include actual track data - before & after - in replies.)

Here's where I'm currently at:

R/T-----------.702
60'----------1.982
330'--------5.679
1/8---------8.746
MPH-------81.02
1000------11.334
1/4--------13.532
MPH------102.64

I'm hoping that with a change to 4.30's & LOTS more track time/practice,
I can get my silver 'vert into the 12's.... :D
 

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Discussion Starter · #3 ·
For comparison's sake, here is what I ran 1st time out earlier this year:

4th run:
March 30th, 2003 @ 5:16 PM
Launched @ 4500 RPM:

R/T-----------.787
60'----------2.248
330'--------6.027
1/8---------9.072
MPH-------81.78
1000------11.653
1/4--------13.85
MPH------102.29

5th/Best run:
March 30th, 2003 @ 6:40 PM
Launched @ 4500 RPM:

R/T-----------.917
60'----------2.190
330'--------5.972
1/8---------9.007
MPH-------81.92
1000------11.596
1/4--------13.77
MPH------103.40


This was with the following:

Stock Comp TA's @ 16 psi
No custom chip or dyno-tune
10 - 17 LESS rwhp across the power band
No tubular k-member or tubular A-arms
Spare tire/jack/other stuff still in trunk
(At that time, car weighed 3830 w/me in it - car weighs 3630 currently w/me in it)
 

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Since drivability was brought up.. What rpm do you 4.56 guys cross the traps at? I know you are in 4th gear, maybe close to 5th.. I figured it would be around 6400.. Am I close in my guessing?
 

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I remember reading some 2 years or so ago one guy picked up .3 changing from 4.10's to 4.56. If you have a 4-valve Cobra and want to drag race 4.56 is the gear to have hands down. A n/a Cobra with bolt ons and 4.56's will run low 12's on slicks with good driving. :hammer
 

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What kind of gains should I see going from 2:73s to 4:56s? Assuming I have traction. Will I lose MPH at the same time? How much should my 60' improve. My best ever is a 2.0:rolleyes:
Current best time in sig...

Darren
 

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I think on your car you would see close to .5 drop. Assuming you run slicks and use the 4.56's torque multiplication to get you out of the hole. The 4.56's will not hurt your MPH either! They will keep the car in it's rpm band longer and therefore put more power down!
 

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4.56's
 

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what gear and rpm do you guys cross the traps in with 4:56's though?? how many r's are you turning freeway speeds, i do alot of freeway here in my town.
 

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4V_GTS said:
What kind of gains should I see going from 2:73s to 4:56s? Assuming I have traction. Will I lose MPH at the same time? How much should my 60' improve. My best ever is a 2.0:rolleyes:
Current best time in sig...

Darren
You have a 96 with 273s? did you or someone put them in? I though the 96s came with 327s. just wonderen.:confused:
 

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Kobra Kahn said:
what gear and rpm do you guys cross the traps in with 4:56's though?? how many r's are you turning freeway speeds, i do alot of freeway here in my town.
DAmn!! doesn't anyone hear my weeping sorrows!! :(
 

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I run around 2800 at 70mph I think. My speedo is not accurate but I checked it upside my wifes truck. When I went 10.47 I only turned ~7100-7200 through the traps. Keep in mind that I am running a 28" tire also which makes a big difference at the track. On the street I run 275/35/18 Kuhmo's.
 

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hey blkcobra, did you cross the traps in 3rd or 4th gear? yeah i know about running ratios, i get what you're saying.
 
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