rear gear change

racer913 · 03-16-2012, 02:59 PM

thanks for the help

63corvette · 03-16-2012, 05:44 PM

Just from my experience:
My old car was a 434 SBC and made almost 850 HP
Powerglide with 1.76 gears
Car weighed 2400 lbs plus without driver
Used 16- 32 inch tires
I started with 4.86 gears and that was a little low as it crossed the quarter mile at 7600 to 7800 RPM
I changed it to 4.56 gears
That did not change the quarter mile ET times but did change the MPH by a few more MPH.
I used the same torque converter. Only change was the rear end gears.
With the 4.56 gears it crossed the quarter mile finish line at 7200 to 7400 and ran high 8 second et's at close to 150 MPH.
Just my experience.
Rick Cates

Geerhead55 · 03-17-2012, 01:37 AM

Rick,, I'm hoping that I don't go through much higher than 7200, since my car isn't tubbed and I don't have room for 32" tall tires and changing gears on a Dana 60 isn't like popping out a pumpkin on a 9 incher. I'll be a lot smarter in a few weeks. Take care.
Danny Durham

03-16-2012, 02:59 PM	#1
racer913 Junior Member Join Date: Aug 2007 Posts: 69 Likes: 2 Liked 0 Times in 0 Posts	Re: rear gear change thanks for the help

03-16-2012, 05:44 PM	#2
63corvette Senior Member Join Date: Mar 2007 Location: Canyon, Tx Posts: 553 Likes: 128 Liked 361 Times in 104 Posts	Re: rear gear change Just from my experience: My old car was a 434 SBC and made almost 850 HP Powerglide with 1.76 gears Car weighed 2400 lbs plus without driver Used 16- 32 inch tires I started with 4.86 gears and that was a little low as it crossed the quarter mile at 7600 to 7800 RPM I changed it to 4.56 gears That did not change the quarter mile ET times but did change the MPH by a few more MPH. I used the same torque converter. Only change was the rear end gears. With the 4.56 gears it crossed the quarter mile finish line at 7200 to 7400 and ran high 8 second et's at close to 150 MPH. Just my experience. Rick Cates

03-17-2012, 01:37 AM	#3
Geerhead55 VIP Member Join Date: Sep 2002 Location: Tacoma, Washington Posts: 1,632 Likes: 0 Liked 5 Times in 5 Posts	Re: rear gear change Rick,, I'm hoping that I don't go through much higher than 7200, since my car isn't tubbed and I don't have room for 32" tall tires and changing gears on a Dana 60 isn't like popping out a pumpkin on a 9 incher. I'll be a lot smarter in a few weeks. Take care. Danny Durham