3.70 or 4.11?
Thread Starter
Racer
Joined: Jul 2001
Posts: 341
Likes: 0
From: macon, ga
3.70 or 4.11?
when i purchased my 77 i was informed that it has 3.70's in it. well i was playing with the rear end claculator at smokemup.com and it looks like i have 4.xx. i run 68 ish at 3500 rpm and 74mph at 3800 rpm. i know i can jack up the car and count the revelutions of the drive shaft but where exactly are the identifications #'s stamped at? and what are they?
thanks
[Modified by ykp53, 11:07 AM 12/14/2001]
[Modified by ykp53, 11:09 AM 12/14/2001]
thanks
[Modified by ykp53, 11:07 AM 12/14/2001]
[Modified by ykp53, 11:09 AM 12/14/2001]
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Re: 3.70 or 4.11? (ykp53)
If someone really put 4.11s in that thing, they must have been sadists (your car didn't come from the factory with that ring and pinion). At any rate, the axle code is on the bottom rear of the housing. You'll have to get on your back -most likely with a scrub brush and flashlight- and read the first two alpha characters. It will be something like AW. You need a reference to decypher the code (like a Chilton's). Don't know how much good that's going to do you though since those gears didn't come in that housing.
Thread Starter
Racer
Joined: Jul 2001
Posts: 341
Likes: 0
From: macon, ga
Re: 3.70 or 4.11? (gerry72)
it wouldn't suprise me they have changed everything else. it was origanily silver with a 350 and 3.08's when the work was done they did a good job. what all is required to put in 4.xx in a car. wouldnt you have to change out the entire pumkin?
Thread Starter
Racer
Joined: Jul 2001
Posts: 341
Likes: 0
From: macon, ga
Re: 3.70 or 4.11? (FeedVaal)
i run 255/60/r15's all around. i have thought about that but doing some calculations there should only be 2 or 3 mph differance. is hter any way to check my calculations? what were stock tires for a 77?
Burning Brakes
Joined: Sep 2001
Posts: 1,166
Likes: 0
From: Tulsa Ok
Re: 3.70 or 4.11? (ykp53)
I run 245/60/15 on really crappy looking aftermarket mags. My spare which I believe is the original is a 235/70/15 but I've never measured it. Hopefully someone will chime in here with the specs for it.
My 245's are 25.5 inches tall.
Sorry should read 225/70/15. Found an online calculater that says it should measure 27.4 high. http://www.ring-pinion.com/calc-tire.html
[Modified by FeedVaal, 2:25 PM 12/14/2001]
My 245's are 25.5 inches tall.
Sorry should read 225/70/15. Found an online calculater that says it should measure 27.4 high. http://www.ring-pinion.com/calc-tire.html
[Modified by FeedVaal, 2:25 PM 12/14/2001]
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Re: 3.70 or 4.11? (FeedVaal)
I was running 4.11 gears and a 245 60 15 tire. I think they are 26.6 tall. I would get about 3600 rpm at about 70. I just switched to 3.70 gears and don't have any speeds yet to talk about. Still have the wrong gear in the tranny
Racer
Joined: Sep 2001
Posts: 354
Likes: 0
From: Prineville Oregon
Re: 3.70 or 4.11? (ykp53)
What other modifications were made? If your running an automatic and the previous owners installed a higher stall converter, that could account for some of the differance in your speed/RPM calculations and what your actually seeing on the street. I have a 4,000 stall converter and show around 500 RPM of "slip" compared to a similar car equipped with a manual tranny. Just a thought...
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Race Director
Joined: Feb 2001
Posts: 10,787
Likes: 0
From: My own state of mind
Re: 3.70 or 4.11? (DeenHylton)
4.11's if you want to say goodbye to gas mileage! I'd only want 4.11's if I was making my car a street/strip only car. Not good for street use. But that's just my opinion. I'd stick with the 3.70's. It's a good gear for street use with a little strip use.
