Where Were 4.11:1 Rear Differentials Used?
09-20-2018, 09:31 PM
#1
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St. Jude Donor '10
Where Were 4.11:1 Rear Differentials Used?
I came across a 4.11:1 rear differential today with HD yokes on it and couldn't help but wonder where someone would use that ratio?
Wouldn't that keep the RPM's high even on a four speed car?
Would it work okay for a five speed or six speed transmission?
Probably give one heck of a hole shot to the car I would guess.
Let me know what you think.
David Howard
Wouldn't that keep the RPM's high even on a four speed car?
Would it work okay for a five speed or six speed transmission?
Probably give one heck of a hole shot to the car I would guess.
Let me know what you think.
David Howard
09-20-2018, 10:00 PM
#2
Safety Car
........at the drag strip, or some spirited street driving. I have 4.11's in my car. Depending on your engine, you gear the car for the RPM you want to cross the finish line in a drag race.
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09-20-2018, 10:41 PM
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St. Jude Donor '12-'13, '15- '16-'17-'18-'19, '21
Both my builds are 4.11s with T56 transmissions.
My 67 Camaro was stock 3.73 but I changed it to a 4.10 in 1969 for my Super T-10 4 spd and drag racing.
All depends upon use of car.
Ideal final ratio for 1st gear is 10.0 achieved by multiplying the first gear ratio of the transmission by the gear ration of the rear end.
I like the 6 spd match up with my 4.11. Will give me "holeshot" off line and highway cruising mpg in 5th and 6th.
Unaware of any "stock" 4.11 in our C3 cars. You will find them in trucks, heavy vehicles, etc to get them moving.
Early hotrodding days 4.33, 4.56, 4.88, 5.13 came out of truck rears and shoe horned into 12 bolt fixed axles in early 60's muscle cars.......
My 67 Camaro was stock 3.73 but I changed it to a 4.10 in 1969 for my Super T-10 4 spd and drag racing.
All depends upon use of car.
Ideal final ratio for 1st gear is 10.0 achieved by multiplying the first gear ratio of the transmission by the gear ration of the rear end.
I like the 6 spd match up with my 4.11. Will give me "holeshot" off line and highway cruising mpg in 5th and 6th.
Unaware of any "stock" 4.11 in our C3 cars. You will find them in trucks, heavy vehicles, etc to get them moving.
Early hotrodding days 4.33, 4.56, 4.88, 5.13 came out of truck rears and shoe horned into 12 bolt fixed axles in early 60's muscle cars.......
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AllC34Me (09-21-2018)
09-20-2018, 11:07 PM
#4
Parts Sherpa
...All depends upon use of car.
Ideal final ratio for 1st gear is 10.0 achieved by multiplying the first gear ratio of the transmission by the gear ration of the rear end.
I like the 6 spd match up with my 4.11. Will give me "holeshot" off line and highway cruising mpg in 5th and 6th.
Unaware of any "stock" 4.11 in our C3 cars........
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AllC34Me (09-21-2018)
09-20-2018, 11:16 PM
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Burning Brakes
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My 68 C-10 1/2 ton was ordered with 4:11 gears and a four speed, heavy duty suspension and tow package. They had something heavy that they needed to move. Truck works well around town, and is very easy to roast the tires. Freeway driving leaves much to be desired. A 5 or 6 speed would be ideal for cruising speeds.
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AllC34Me (09-21-2018)
09-21-2018, 12:27 AM
#7
Race Director
My 62 has a 4:11 in it. It turns around 3000 at 60 mph, and with the 16 gallon tank, it doesn't go much more than about 100 miles between fill ups. I also have a 3:08, that I use to throw in the car, if I was planning a long trip. The rears are pretty easy to change in the early cars, and I could swap center sections in less than an hour.
A 5 or 6 speed would be nice, but I don't use the car much anymore, so I'll live with the 4 speed for now.
A 5 or 6 speed would be nice, but I don't use the car much anymore, so I'll live with the 4 speed for now.
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AllC34Me (09-21-2018)
09-21-2018, 06:11 AM
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St. Jude Donor '10
All great answers, thank you for responding.
I wound up putting 3.73 in my road race replica and a TKO five speed. Next race build might include the 4.11 and a six speed, will have to crunch the numbers.
Thank you again, appreciate the comments.
Best regards,
David
I wound up putting 3.73 in my road race replica and a TKO five speed. Next race build might include the 4.11 and a six speed, will have to crunch the numbers.
Thank you again, appreciate the comments.
Best regards,
David
09-21-2018, 06:43 AM
#10
Race Director
Highway speeds have also gotten much higher. We had 55 and some 65 mph speed limits and people actually did those speeds with maybe 5 mph above. So the engines were not turning quite as fast and gas was cheap. We now travel the highways at 80 to 90 mph. So OD transmissions Are a blessing in order to maintain some type of fuel mileage.
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09-21-2018, 06:47 AM
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St. Jude Donor '10
Highway speeds have also gotten much higher. We had 55 and some 65 mph speed limits and people actually did those speeds with maybe 5 mph above. So the engines were not turning quite as fast and gas was cheap. We now travel the highways at 80 to 90 mph. So OD transmissions Are a blessing in order to maintain some type of fuel mileage.
09-21-2018, 09:23 AM
#12
Melting Slicks
Best you could get with the standard M20 was a 3.70
OR
You needed a M21 to get a 4.11
You sure you don't have a M21 or a 3.70 rear?
Last edited by Hammerhead Fred; 09-21-2018 at 02:11 PM.
09-21-2018, 09:43 AM
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Royal Canadian Navy
I'm enjoying my 4.11/M21 combo. I only go through a few tanks of gas in the summer so I could not care less about my 10 mpg fuel economy.
Dennis, the rear end is working just fine!
Dennis, the rear end is working just fine!
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AllC34Me (09-21-2018)
09-21-2018, 09:55 AM
#14
Safety Car
09-21-2018, 01:55 PM
#16
Melting Slicks
I have a 4.11 in my 75 Vette with a 700R4. It cruises very well on the highway and if you can get the tires to hook, it accelerates very hard.
Mike
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AllC34Me (09-21-2018)
09-21-2018, 02:06 PM
#17
Safety Car
But a very nice car you have there !!!
My car is a # 69 L46 with M21 and 3.70 from the factory.
Last year I installed a T5WC 5 transmission with 0.63 in 5th gear.
https://shiftsst.com/articles/1968-1...perfectfit-kit
09-21-2018, 02:08 PM
#18
Safety Car
I used to have a 63 2 door post Biscayne hot rod back in the 70's, which had the same pumpkin differential as your 62. I broke more than my share of these rear ends and got pretty quick at changing them.
I have a 4.11 in my 75 Vette with a 700R4. It cruises very well on the highway and if you can get the tires to hook, it accelerates very hard.
Mike
I have a 4.11 in my 75 Vette with a 700R4. It cruises very well on the highway and if you can get the tires to hook, it accelerates very hard.
Mike
09-21-2018, 02:16 PM
#19
Drifting
They were used where people wanted to have some fun!
We measure gas consumption in smiles per gallon, it is a Corvette after all.
That reminds me, David my rear end was a 4:11 when you had it rebuilt correct?
We measure gas consumption in smiles per gallon, it is a Corvette after all.
That reminds me, David my rear end was a 4:11 when you had it rebuilt correct?
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Metalhead140 (09-22-2018)
