Help me pick a rear gear ratio?

[Brads70]

Ok trying to figure out what rear gear I need to order in the Dana  ( might order one in a month for the Javelin?)   
I'm thinking 4.56 ?  Check out this tremec gear  calculator ( select Magnum XL 2.66 as it has the same gears ratio my 6 speed has)  rear tire size is 27.2" for 295/40/18 or 26.6 for 295/50/15 tires. Cam I'm looking at for my 401 is the lunati 702 or 703 ( 702 says power band is 1600-5800, 703 is 2000-6000 )
https://issuu.com/lunati-power-development/docs/l2013vt_web/18 
So I'm figuring I need to figure a gear for 6th gear (.50 ratio) that gives me 2000 rpm at 65-70 mph ?  Seems 4.56 is the ticket? Dana is available with 3.55, 3.73, 4.10, 4.30, or 4.56, 4.88 and up are available too?
Am I missing something?  What will 1st-4th gears be like? Useless in 1-2 gears? Check out this calculator? Fun to play with...
http://tremec.com/calculadora.php

[GoodysGotaCuda]

I have 3.73 with a 28.5" tire and the 2.97 T56 magnum. The RPM of mine compared to a 4.56 in your car seem more similar than I expected, though your driveshaft speed will be at warp-speed running down the highway with 4.56s

I would be targeting to run at ~1650-1750 with a 0.50 6th gear and see what axle ratio gets you there.

[Brads70]

I have 3.73 with a 28.5" tire and the 2.97 T56 magnum. The RPM of mine compared to a 4.56 in your car seem more similar than I expected, though your driveshaft speed will be at warp-speed running down the highway with 4.56s

I would be targeting to run at ~1650-1750 with a 0.50 6th gear and see what axle ratio gets you there.

Can you get into 6th gear without needing bail money ? My first thoughts was 3:73 but after looking at the numbers I'm not so sure now?  I made the mistake of not ordering the right gear with the Dana in the Challenger and had to change it, trying to not make the same mistake twice ?

[GoodysGotaCuda]

I spend lots of time in 6th, but i also have the .63 close-ratio trans. I cruise at 65 at 1840 and 80mph at 2,200rpm.


Here is yours @ 4.56 vs mine @ 3.73

[GoodysGotaCuda]

https://www.blocklayer.com/rpm-geareng.aspx

link

[Brads70]

https://www.blocklayer.com/rpm-geareng.aspx

link

I've been playing with this one. You can change the gear ratio's in both the transmission and rear end to suit your needs. I have it so 3rd and 4th are OD ratio's in my T56. 4:30 might be a good compromise also? I guess it depends on what cam I choose?

https://www.e-bodies.org/resources/rpm-speed-gear-tire-size-calculator/

[Brads70]

https://www.blocklayer.com/rpm-geareng.aspx

link

Thanks, That is a good one to play with

[Brads70]

I spend lots of time in 6th, but i also have the .63 close-ratio trans. I cruise at 65 at 1840 and 80mph at 2,200rpm.


Here is yours @ 4.56 vs mine @ 3.73

I think I like your T56 gear ratio better than mine LOL . But I've only got $1500 Canadian into mine and I couldn't pass it up.

[Brads70]

I have 3.73 with a 28.5" tire and the 2.97 T56 magnum. The RPM of mine compared to a 4.56 in your car seem more similar than I expected, though your driveshaft speed will be at warp-speed running down the highway with 4.56s

I would be targeting to run at ~1650-1750 with a 0.50 6th gear and see what axle ratio gets you there.

@GoodysGotaCuda    Just doing some calculations..... to get driveshaft rpm(speed)  I take engine RPM then divide it by OD ratio right?
so say 2000 rpm would be ( in my case) 2000 divided by .5 which equals 4000 rpm

[1 Wild R/T]

I have 3.73 with a 28.5" tire and the 2.97 T56 magnum. The RPM of mine compared to a 4.56 in your car seem more similar than I expected, though your driveshaft speed will be at warp-speed running down the highway with 4.56s

I would be targeting to run at ~1650-1750 with a 0.50 6th gear and see what axle ratio gets you there.

@GoodysGotaCuda    Just doing some calculations..... to get driveshaft rpm(speed)  I take engine RPM then divide it by OD ratio right?
so say 2000 rpm would be ( in my case) 2000 divided by .5 which equals 4000 rpm

Correct...

[Chryco Psycho]

I would pick a ratio where 1-5th gear is more useful & use the .5 ratio 6th gear less

[RUNCHARGER]

Yup: #6 in my Viper is a bit too tall, mind you I'd have to pedal 1st and 2nd even more if they were lower.