Ideal rear gears?
Thread Starter
Team Owner
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St. Jude Donor '11, '16-'17
Ideal rear gears?
engine: 496 BB, 9.9:1, hydraulic roller cam (either a comp XR288R or XR294R), 500+hp, 575lbs torque.
Trans: Muncie M20
Currently the rear gears are 4.11:1, but I currently have it completely apart to replace the bearings. I have a feeling that 1st gear will be all but useless with the above combination. What do you guys think? I'm leaning towards 3.23:1.
Trans: Muncie M20
Currently the rear gears are 4.11:1, but I currently have it completely apart to replace the bearings. I have a feeling that 1st gear will be all but useless with the above combination. What do you guys think? I'm leaning towards 3.23:1.
Melting Slicks
Joined: Nov 2003
Posts: 2,362
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From: San Antonio TX
There really is no perfect gear. You have to decide what you want out of the car. Then decide what type of gear you would like to run. There is always a trade off. 
But for the street I tend to like 3.73 or 3.55 but they are very close.
But for the street I tend to like 3.73 or 3.55 but they are very close.
Team Owner
Joined: Nov 2004
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From: Sorrento Italy
i have 4.11 rear gears as well, with a t-10 trans and about 570hp in the hood...i love the 4.11, of course i feel my fearless t-10 is going to pay the bill pretty soon...also you should get a hurst comp shifter to be able to shift gears quick and before the short rear puts the revs over the limit at every change
Team Owner
Joined: Jul 1999
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From: Orange Park Florida
IMO, with that kind of torque, or anything even close.....go with a 308 rear, the car will move out fine.....unless you got a overdrive, then you can compromise on 336 or so....
unless you plan a LOT of drag racing with minimal street useage....then it's a whole differant ballgame...
unless you plan a LOT of drag racing with minimal street useage....then it's a whole differant ballgame...
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by SHAKERATTLEROLL
There really is no perfect gear. You have to decide what you want out of the car. Then decide what type of gear you would like to run. There is always a trade off.
But for the street I tend to like 3.73 or 3.55 but they are very close.
But for the street I tend to like 3.73 or 3.55 but they are very close.
3.55 would be perfect for that but the M20 will bite the dust in short order behind that motor. 3.55 is a nice gear with the TKO 600 as well.
Burning Brakes
Joined: Jan 2006
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From: Same as our leaders Out of my mind
383 Stroker with a Richmond 5 speed here, with a 1:1 5th gear ratio. I had a 3:73 rear but found it to be geared too low. I just switched to a 3:36 and feel that the car has much better gear range and driveability. The 3:73's had me costantly "rowing" the shifter, now I shift less and get less highway noise. The car still launches pretty nice in 1st gear too.
My .02
My .02
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Thread Starter
Team Owner
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St. Jude Donor '11, '16-'17
Yeah, I know the M-20 is weak, but I just spent $800 having it rebuilt with a heavy duty tail housing. I think the tires will provide an escape valve for all the torque for a while. Eventually, I'll either go with an automatic, or a Tremec TKO-600.
My mechanic has been great. He's retired and now just plays with his drag car and takes on special projects that interest him. He's been letting me work with him as his gopher while he works on my car. It's been an incredible learning experience. He's recommending 3.23:1. His car is a stripped down Dodge Polara with a 440. He said that he went from 4.11:1 to 3.23:1 and because his engine makes so much torque, he only lost a tenth of a second at the track and actually gained trap speed.
My mechanic has been great. He's retired and now just plays with his drag car and takes on special projects that interest him. He's been letting me work with him as his gopher while he works on my car. It's been an incredible learning experience. He's recommending 3.23:1. His car is a stripped down Dodge Polara with a 440. He said that he went from 4.11:1 to 3.23:1 and because his engine makes so much torque, he only lost a tenth of a second at the track and actually gained trap speed.
Last edited by The_Dude; Nov 18, 2006 at 03:11 PM.
Team Owner
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From: All humans are vermin in the eyes of Guru VA
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3.73 for the XR288 cam
4.56 for the XR296 cam
Compcams doesnt provide a lot of information, but crane cams does. So I compared the above cams with the crane equivilant which provides cruise ranges. I took both cruise ranges, took 400rpm off of them to account for your longer stroke, and used the Keisler RPM analyzer to put 55 in as close to the low end of the range as possible.
4.56 for the XR296 cam
Compcams doesnt provide a lot of information, but crane cams does. So I compared the above cams with the crane equivilant which provides cruise ranges. I took both cruise ranges, took 400rpm off of them to account for your longer stroke, and used the Keisler RPM analyzer to put 55 in as close to the low end of the range as possible.
Drifting
Joined: Mar 2006
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From: Oak Ridge NC
Originally Posted by mrvette
IMO, with that kind of torque, or anything even close.....go with a 308 rear, the car will move out fine.....unless you got a overdrive, then you can compromise on 336 or so....
unless you plan a LOT of drag racing with minimal street useage....then it's a whole differant ballgame...
unless you plan a LOT of drag racing with minimal street useage....then it's a whole differant ballgame...
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
My 67 Camero has a M-21 and a 2.73 rear end. It's a little hard to launch. But once it's going it's great. My Vette is 4.11 and a TKO 600. The first 4 gears are a good time and the OD is for the freeway.
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From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
I'm running 3.08's with an M-22. In first gear the tires won't break loose unless I run the rpm's to about 3500.
I've got a 4:11 rear I'm going to eventually swap. I also have an M-20 that I can experiment with.
I've got a 4:11 rear I'm going to eventually swap. I also have an M-20 that I can experiment with.
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
Originally Posted by Bob Onit
How long will that Muncie hold up?
Man..... thats gotta be one hell of a seat of the pants ride
Man..... thats gotta be one hell of a seat of the pants ride
I feel on street tires 4.11's are just too much IF you have a descent motor.
I like my 308's
Team Owner
Joined: Nov 2004
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From: Sorrento Italy
Originally Posted by norvalwilhelm
I actually found that with my bigblock and 4.11 gears I could not use 1st gear. Anytime I got on it the tires just went up in smoke. I switched to 308's and liked them alot better for off the line acceleration.
I feel on street tires 4.11's are just too much IF you have a descent motor.
I like my 308's
I feel on street tires 4.11's are just too much IF you have a descent motor.
I like my 308's
Instructor
Joined: Oct 2005
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From: Independence MO
You have to deside how you are going to drive the car. IF you are using it on the hiway a lot you would be better off with a gear at 3.55 or a little lower. With the HP you have 3.08 would be good. You should be able to do 50 MPH in first gear!!
Race Director
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From: Waterloo ontario Canada
Originally Posted by panic
norval, if you'd drive around a nice winding road with sharp bends and U turns uphill you'd choose a 4.11....power shifting with 570hp under the hood and this short gear just before a quick approching bend is paradise on heart, believe me
I ran those 4.11 gears for about 18 years and really got sick of them. I switched back to the stock 308's and found them alot more controllable on the road.
Trust me you could not do a U turn or a tight turn and punch it with my car. It would just wipe out.