Gear Ratio Recommendations
February 17th, 2008, 10:36 AM
#1
Dr.Olds Illegitimate Son
Thread Starter
Join Date: Apr 2007
Location: Katepwa Lake, Sk Canada
Posts: 104
Gear Ratio Recommendations
Hi all,
I have a '71 Cutlass Supreme ragtop that I would like to upgrade the rearend with.
Its a 10 bolt that is open. I'm sitting at around 360 hp with the motor , but it just doesn't hava a lot of snap off the line. Pulls like a damn on the highway.
I would like to go to posi and more umph, but still highway drivable.
Your thoughts ?
I have a '71 Cutlass Supreme ragtop that I would like to upgrade the rearend with.
Its a 10 bolt that is open. I'm sitting at around 360 hp with the motor , but it just doesn't hava a lot of snap off the line. Pulls like a damn on the highway.
I would like to go to posi and more umph, but still highway drivable.
Your thoughts ?
February 18th, 2008, 02:48 AM
#2
Registered User
Join Date: May 2006
Location: MD/DC
Posts: 46
Would you happen to know the gear ratio currently? Im going to assume you have 2.xx gears and a 3-speed.
If my assumptions are correct, then a think 3.08's-3.23's gears are the sweet spot for highway and street!
Ed
If my assumptions are correct, then a think 3.08's-3.23's gears are the sweet spot for highway and street!
Ed
February 21st, 2008, 06:40 PM
#4
New 4-4-2 Owner
Join Date: Jan 2008
Location: Phoenix, AZ
Posts: 41
hmm, i do agree that the 3.23 gear ratio is a good one. But don't overlook the 3.55 gear. Gives a little more lower end torque response for a snappy start off the line, yet retains a good amount of drive-ability on the highway.
Myself speaking, my 67 442's 400 BB motor currently has a 4.33 rear-end gear ( stock from the NC Dealer) to go through. Great for blasting off the line with, but I can't drive it on the highway.
Anyhow, just my own humble opinion. Good luck with the project.
desert442
Myself speaking, my 67 442's 400 BB motor currently has a 4.33 rear-end gear ( stock from the NC Dealer) to go through. Great for blasting off the line with, but I can't drive it on the highway.
Anyhow, just my own humble opinion. Good luck with the project.
desert442
February 21st, 2008, 08:12 PM
#5
Junior Member
Join Date: Oct 2004
Location: Southern CA
Posts: 2,212
February 21st, 2008, 09:17 PM
#6
Registered User
Join Date: Jul 2007
Location: Tucson, AZ
Posts: 224
What RPM's are you guys getting at 65-75 miles per hour? I have a TH400 and my third gear is a 1:1 so it would seem that my RPMs would be a lil high. I haven;t been able to ID my rear but I think its a 3.42. Its a stock 12 bolt 68 442 rear.
Last edited by Jolly Green; February 21st, 2008 at 10:33 PM.
February 22nd, 2008, 03:38 PM
#9
same but different
Join Date: Jun 2007
Location: Central Missouri
Posts: 2,873
I will be installing a 3:23 geared O rear....just waiting for the snow to melt 
I can't wait to replace the 2:56 open rear.
I have it figured to up the rpms by about 600. From 22-2300 to 2800rpm or there abouts, at highway speed.
Don't forget your speedometer reading. You"ll need a new driven gear at the tranny. In my case, a 29 tooth.
I can't wait to replace the 2:56 open rear.I have it figured to up the rpms by about 600. From 22-2300 to 2800rpm or there abouts, at highway speed.
Don't forget your speedometer reading. You"ll need a new driven gear at the tranny. In my case, a 29 tooth.
February 23rd, 2008, 02:27 AM
#10
Junior Member
Join Date: Oct 2004
Location: Southern CA
Posts: 2,212
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