rearend gears

[quickjagg]

I have an 81 with an RPM intake, headers, dual exhaust, 600cfm carb, and an auto trans. I was looking at replaceing the rearend gears this winter and was wondering what you guys suggest I should put in it. I use the vette for everyday driving in the summer, so I don't want anything too crazy for gears, but I would like to feel the car pull harder.

Thanks for the help guys!

-Chris

 

[JLMvette73]

Chris,
I swapped the original 3.08 in my '73 for a 3.73. I'm more than satisfied with the results. When I hammer the gas, it'll pin me to the back of the seat at every shift. The car has a 350 TH that has a B & M street/strip shift kit installed. The only mods to the the engine are a set of full length headers, a small comp cam, and reworked stock heads( 3 angle valve job, etc.) The intake and carb are stock.

Jerry

 

[Glensgages]

quickjagg
I was talking this past week to an '81-owner on 'another' Forum, discussing gear-swaps. I think I figured if you have an '81 with 2.87s, the THM350-C (lock-up converter), and 27" tires (BFG 255/60R15s), you'll turn 2125 RPM @ 60 MPH, in 3rd, with lock-up.
If my calculations are correct (check your tach next time), you can figure (approx) RPM @ the same (60) MPH by simply dividing the 'next' ratio by your current ratio, then multiplying THAT # by the 2125 RPM you turn now.
For instance, if you swap-out to 3.73s, you'd figure it this way:
3.73 divided by 2.87 = 1.299. Then multiply 2125 by 1.299, to equal 2761 RPM.
Just for your info, I'm told that going from 2.87s to 3.73s in lo-po C3 like ours (I have a Cross-Fire :eyerole ) will result in an ET improvement of from .3 to .5 seconds.
If you decide to get new gears, but can't find them, let me know. I got a set of 3.73s recently for $135, including S&H.....

 

[MaineShark]

Just a thought, but a few companies offer whole, rebuilt rear ends with a choice of ratios.

Maybe someone knows better, but wouldn't it be possible to buy the stronger '79-and-earlier rear for an '80-82 Shark? I think I heard somewhere that they are externally identical...

Might be a way to eliminate that potential weak link...

Joe

 

[Glensgages]

Maybe someone knows better, but wouldn't it be possible to buy the stronger '79-and-earlier rear for an '80-82 Shark? I think I heard somewhere that they are externally identical...

I think I've been told the '80-'82 differentials (themselves) ARE externally the same, but internally different, AND all related components (axles, etc.) are different, too!
Also told as long as I keep it under 350 HP behind an automatic, the Dana44 housing 'should' survive, so, I'll give it a try...

 

[Tom Bryant]

Gear Ratio Calculators

Check out the Tool Box section under the Tech Center tab at the top of this page. There are several calculators there that will take the stress off your brain and do all the figuring for you. I use them often.

Tom

Glensgages

That's one of my favorite Dale Earnhardt quotes. I can actually see him saying it in my mind.

 

[Glensgages]

Re: Gear Ratio Calculators

That's one of my favorite Dale Earnhardt quotes. I can actually see him saying it in my mind.

I understand he said that in one of, if not the, last interviews 'before'.
I've also been told that the last 'known' photo of Big E was standing next to a guy that lives less than 20 miles from me, on pit-road that morning. The story goes, the 'local' had failed to qualify that year, but was offering good luck wishes to those who had. Right before Earnhardt swung his leg into the window, the 'local' offered Big E his hand, a picture was snapped, he got into his car,....and the rest is history. Haven't been able to 'confirm' this, but I'd sure like a copy of that picture...

You ever hear the story Jeff Gordon tells about his 1st time, going down the back-stretch @ Daytona alongside Earnhardt?

 

[Tom Bryant]

Re: Re: Gear Ratio Calculators

I

You ever hear the story Jeff Gordon tells about his 1st time, going down the back-stretch @ Daytona alongside Earnhardt?

At the risk of taking this thread even further off topic...no.


On topic.

3.73s would be good for around town and limited road use but I don't think you would like them for cross country unless you have and overdrive top gear.

Tom

 

[Glensgages]

Briefly: Feb '93 Speedweeks in Daytona, as told by Jeff Gordon, where he is competeing for the first time ever.
During a mid-week open-practice, Gordon finds himself going down the back-stretch, in the middle of a 3-way sandwich.
He looks out his right window, to see Ken Shrader, his eyes as big as baseballs, gazing straight-ahead, and his hands gripping the wheel so tight, Gordon said he could 'see' white knuckles, UNDER the gloves!
Gordon looks out his own side-window, only to see Dale Earnhardt himself, right hand on the steering wheel, left hand in front of his own face, fingers extended & 'wiggling', as if to say "HI!!!" , and Earnhardt staring Gordon right in the eye, with his trade-mark cock-eyed grin on his face...
All this, at 185+ MPH!!!!!
GAWD, I miss that guy.....

about the gears: I once drove my Z28 600-miles, round-trip, with 4.10s & a 9"/4000 stall converter; I had to be nucking futs!
SUNOCO stock went thru the roof that month.....

 

[1BAD80]

80-82 had different external housings (spring mounted different) and a Dana gear set, the front has the mounting tab built in 1unit.
They are not the same. The size is the same for build of the car.