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Rearend gear selection help needed. #2413734
12/05/17 07:00 PM
12/05/17 07:00 PM
Joined: May 2009
Posts: 831
Missouri
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galen Offline OP
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galen  Offline OP
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Missouri
This is mainly a cruise night type car that will be making a few 100 plus mile trips for shows, etc. 68 Plymouth Satellite. Engine is a 588, Koleno block, 572-13 heads. Peak torque 817 at 6200. Redline 7000rpm. Tires are M&H 325/45/17 drag radials 28" diam. I am a paraplegic and drive with hand throttle and brake. In turn I opted for a fully programmable TCI 6X with upgrades. Gear ratios are 2.97,2.23,1.57,1.18,1.00,0.75. 3600 stall. I am leaning toward a 3.73 in a Strange S60. I want acceleration more than top end. It is a heavy all steel car, AC etc. I value your opinions. Thanks, Galen

Re: Rearend gear selection help needed. [Re: galen] #2413739
12/05/17 07:09 PM
12/05/17 07:09 PM
Joined: Jan 2003
Posts: 3,830
N.E. Ohio
6bblFLASH Offline
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N.E. Ohio
Even a 3.54 would be plenty,Thats a healthy engine!!


70` Cuda`,440 6BBL Jerico,Dana 4.56 Still on 93 Pump Gas
9.87 @ 136/1.31-60ft.`09 Mopar Nationals PASSON PERFORMANCE "Stick-Shift" Champ!
2013 StickShift Challenge Winner@ Mopar Nationals!
Re: Rearend gear selection help needed. [Re: 6bblFLASH] #2413751
12/05/17 07:21 PM
12/05/17 07:21 PM
Joined: Dec 2004
Posts: 10,549
Rittman Ohio
fourgearsavoy Offline
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Rittman Ohio
Yeah with that 2.97 first gear a 3.54 will be plenty. I had a 3.27 low gear in my Richmond and 3.54 gears in the rear and it came out of the hole quite nicely thumbs

Gus beer

Last edited by fourgearsavoy; 12/05/17 07:21 PM.

64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
Re: Rearend gear selection help needed. [Re: fourgearsavoy] #2413752
12/05/17 07:22 PM
12/05/17 07:22 PM
Joined: Jan 2003
Posts: 13,318
Marion, South Carolina [><]
an8sec70cuda Offline
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an8sec70cuda  Offline
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Marion, South Carolina [><]
iagree With that first gear ratio and a 28" tall tire, I'd go w/ 3.54s.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: Rearend gear selection help needed. [Re: galen] #2413801
12/05/17 08:28 PM
12/05/17 08:28 PM
Joined: Mar 2006
Posts: 9,791
MI, usa
dvw Offline
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dvw  Offline
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MI, usa
Even a 3.54 has more starting line ratio than a dedicated drag car needs at this power level. Definitely doesn't need any more than this. My 9.0 drag car 2.45x4.30=10.54 (too much) with 10.5wx31, for comparison 2.97x3.54=10.51 on a 28" which are 10% shorter
Doug

Re: Rearend gear selection help needed. [Re: galen] #2413840
12/05/17 09:44 PM
12/05/17 09:44 PM
Joined: Dec 2005
Posts: 11,408
Fulton County, PA
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CMcAllister Offline
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Fulton County, PA
3.73 or even a 3.54 with those gear ratios? It's going to be a tire baking machine. Honestly, if you could eliminate using the 2.97 and just use 2.23 as low gear, it would work much nicer I think. Then maybe the 3.73 is manageable. 3.73x2.23=8.32 And with the overdrive, it will be OK on the highway.


If the results don't match the theory, change the theory.
Re: Rearend gear selection help needed. [Re: galen] #2414162
12/06/17 01:29 PM
12/06/17 01:29 PM
Joined: Jan 2003
Posts: 13,318
Marion, South Carolina [><]
an8sec70cuda Offline
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an8sec70cuda  Offline
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Marion, South Carolina [><]
dvw...I agree that even a 3.54 w/ his 1st gear is too much SLR for his motor, but (as you know) the 3.54 is the lowest numerically commonly available gearset for the Dana. If he could find a taller gear, not sure what Strange has for them, that'd definitely be better.
The car is set up more like a street cruiser even though it has a serious motor, so the 3.54 will likely be fine for him. It'll be like driving on ice from a dig though w/ that SLR and 17" drag radials on the street.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: Rearend gear selection help needed. [Re: galen] #2414256
12/06/17 04:06 PM
12/06/17 04:06 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Cab_Burge Offline
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Cab_Burge  Offline
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Bend,OR USA
First of all on a street car with that much power and torque along with a trans that you could start out in second gear I would not use radial tires of any sort on that combination on your car tsk twocents
I've had a lot of race cars and Hi Po street cars(both 4 speeds and automatics trannys) with a lot of different sizes, brands and types of rear tires, the radials on a good track are faster and better, not so on the street shock puke
I would buy another set of wheels and put the biggest size M.T. ET street tires(maybe even a set of Hoosiers scope confused) I could fit on the car for street use, you will have to let air out to make them wheelie on the street though devil boogie
Good luck, be safe and have fun up
As far as the rear gear ratio sit down with a calculator and do the math on each rear gear ratio along with the 1st and 2nd gear ratio in the tranny and then decide which starting line ratio you think you want for racing and maybe a 4.10 or a Dana 61 with 3.30 ratio will work scope shruggy
I've race a 4 speed car on the street and started out in second gear with a NP 833 non O.D. to limit the tire spinning whistling devil up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Rearend gear selection help needed. [Re: Cab_Burge] #2414574
12/07/17 04:04 AM
12/07/17 04:04 AM
Joined: May 2009
Posts: 831
Missouri
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galen Offline OP
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galen  Offline OP
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Missouri
Thanks for the replies. 3.54 is about as high as I can go with the Dana 60. I have not bought my wheels and tires or ordered my rearend yet, but I am ready to do so.. On the front I can run a 16 inch wheel the smallest for the disc brake size I have. I am not locked into a 17 inch for the rear and could order my disc brake size accordingly. Car is mini tubbed to the rails and currently has a 3 inch relocation kit on it. I believe I can run up to a 29 1/2 inch tire without having to do anything to the outer wheel wells. As Cab brought up is there a better tire option that you would suggest? Bias ply, MT ET street or Hoosier. Car will not see wet weather. Thanks again. You guys have given me a lot to think about. Galen

Re: Rearend gear selection help needed. [Re: galen] #2414612
12/07/17 11:31 AM
12/07/17 11:31 AM
Joined: Jan 2003
Posts: 13,318
Marion, South Carolina [><]
an8sec70cuda Offline
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an8sec70cuda  Offline
I Live Here

Joined: Jan 2003
Posts: 13,318
Marion, South Carolina [><]
Pros and cons both ways on the tires. The drag radials drive a lot better, but won't hook nearly as good on the street as a bias ply tire. If you're concerned w/ traction, go w/ a bias ply tire but use a sticky one...like the Hoosier Quicktime Pro or M/T ET Street. Don't waste your time w/ a M/T sportsman or the normal quicktime tire. They are bias ply, but will handle like one AND not hook worth a damn.

If traction is your main concern, stick w/ a 15" rim.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: Rearend gear selection help needed. [Re: galen] #2414641
12/07/17 12:39 PM
12/07/17 12:39 PM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
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polyspheric  Offline
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Joined: Oct 2007
Posts: 4,205
New York
What does your converter manufacturer say is your minimum cruise RPM for acceptable converter slip?


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