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What gears?

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Old 05-16-2016, 08:38 PM
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Well I got my new Factory 5 wheels in but it looks like I to need to change my rear end! The good news is I already have a disc brake rear end which is the right width! I will be rebuilding it and putting a new posi and gears in it. I currently have 4.10's but I'm thinking maybe 3.73's, 355's?


Cobra Kit Car about 2200-2300 pounds, LS-3 525hp, 125hp NOS, 28" tall 295-55-15 M/T drag radials, T-56 Mag
2.66 (1), 1.78 (2), 1.30 (3), 1.00 (4), 0.80 (5), 0.63 (6)


It's a street toy with a trip now and then to the 1/4 mile strip! I just retired and I'm moving to Florida in the next year. I hope to do a lot of day trips!


What ya think?


Al
Old 05-17-2016, 12:06 AM
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You can get away with a lot of gear with a 28" tire and a T-56. That said, it's hard to say without having a good idea of trap speed expected. You might see 135-140mph in the 1/4 if it all works and hooks and those power numbers are accurate and your weight number is accurate. With a 3.90 gear, 140mph is roughly 6500rpm. And 60mph in 6th is about 1750rpm.
Old 05-17-2016, 09:07 AM
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I would go with the 3.73's if it's more for the street. You will have a nice 4th gear for around town and be able to cruise the highway at 75mph just over 2100 RPM in 6th.

If you want quicker ET's and do more track then I wold stick with the 4.10's you've got now. It will put you around 2400 rpm at 75mph.

I'm currently running 4.11's with my T56, but I've got a 31" tall tire.
Old 05-17-2016, 10:55 AM
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I'm for sure leaning 3.73's with the power curve of the LS-3, the T-56, light weight and how I plan to use it!


Thanks guys,


Al
Old 05-17-2016, 01:29 PM
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I ordered up 3.90's for mine, but have almost double your weight and a shorter tire...so we will have to see how they work out. Might have to step down to 3.55's or so.

Your car is going to fly!
Old 05-18-2016, 10:36 PM
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I would go 3.73 or 3.42 .I have an ls @ 500 hp w/3.73 .tire height 24.5 80 mph@ 3100 rpm in od .(.75) florida is a lot of hyway driving 3.42 s are good all around gear .came stock in turbo buicks
Old 12-04-2016, 07:48 PM
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I wound up doing 3.55 gears with 295/55/15 M/T 27.8" tall drag radials.


Al



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