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81 ring and pinion replacement?

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Old Apr 24, 2014 | 02:50 PM
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Default 81 ring and pinion replacement?

Looks like I need some rear end bearings replaced. Since it will already be open.......


Am looking at replacing my ring and pinion with something a little more 'torque-y". It's an original 4 speed with a 2.72 rear end. It's a daily driver, so not going to the track just want to 'chirp some brodies a little easier.'

What ratio do you all recommend?

What spline count on the pinion do I require for an aftermarket one to connect to my stock drive shaft?

Thanks.
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Old Apr 24, 2014 | 04:14 PM
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3.55 or even 3.70 would be real good. If you dont do a lot of freeway driving 3.70 will really wake things up It will make your off the line pull way faster
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Old Apr 24, 2014 | 04:33 PM
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Originally Posted by Bromleys Corvettes
3.55 or even 3.70 would be real good. If you dont do a lot of freeway driving 3.70 will really wake things up It will make your off the line pull way faster
Thanks for the info. What kind of RPM at 60mph am I looking at with those ratios?

Unfortunately, it will be doing a decent amount of highway driving.

Any input on the spline count I would need for any of the after market pinion to fit on my 81's pinion flange?
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Old Apr 24, 2014 | 04:48 PM
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I would leave the 2.72s in it and swap the 4 speed to a Richmond 5 speed
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Old Apr 24, 2014 | 04:51 PM
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Thanks qwank,

Interesting option..... Any where I should look for the 5 speed?
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Old Apr 24, 2014 | 07:24 PM
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Summit and jegs sells them. I have one in my '81. Low 1-4 gears and 1:1 5th. You get the good acceleration and your highway rpms stay the same as they are now
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Old Apr 24, 2014 | 07:41 PM
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Originally Posted by qwank
Summit and jegs sells them. I have one in my '81. Low 1-4 gears and 1:1 5th. You get the good acceleration and your highway rpms stay the same as they are now
qwank...just saw the info on your 383...i'll bet your vette pulls hard and got some crazy top end...with those gears!!
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Old Apr 24, 2014 | 09:09 PM
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Originally Posted by qwank
Summit and jegs sells them. I have one in my '81. Low 1-4 gears and 1:1 5th. You get the good acceleration and your highway rpms stay the same as they are now
Replacing the stock tranny sounds like a good plan but not a cheap option! Anyone got a lead on a good used one?
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Old Apr 24, 2014 | 10:03 PM
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We are talking C3 Corvettes here, unfortunately having a "cheap" mindset is not going to accomplish much. You can pay now or pay later, but you will pay.

Rebuilding a differential is going to cost $1100. Because:

a) Labor is $400 (unless you do it yourself and not many people can do this, I would advise against it unless you've done it successfully before)

b) parts are another $400 because to do it right you need to replace the bearings also

c) It will cost another $200 to rebuild the positrak, and chances are, yours will need rebuilding.

d) taxes

So, you could probably find another diff on ebay for about $1100 with a 3.55 already in it, rebuilt. Might as well buy it and be done with it and sell your as a core.

Your welcome
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Old Apr 24, 2014 | 10:24 PM
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Originally Posted by bebezote
qwank...just saw the info on your 383...i'll bet your vette pulls hard and got some crazy top end...with those gears!!
I wish I had a 383, I still have the stock engine
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Old Apr 24, 2014 | 10:57 PM
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Originally Posted by htown81vette
We are talking C3 Corvettes here, unfortunately having a "cheap" mindset is not going to accomplish much. You can pay now or pay later, but you will pay.

Rebuilding a differential is going to cost $1100. Because:

a) Labor is $400 (unless you do it yourself and not many people can do this, I would advise against it unless you've done it successfully before)

b) parts are another $400 because to do it right you need to replace the bearings also

c) It will cost another $200 to rebuild the positrak, and chances are, yours will need rebuilding.

d) taxes

So, you could probably find another diff on ebay for about $1100 with a 3.55 already in it, rebuilt. Might as well buy it and be done with it and sell your as a core.

Your welcome
Appreciate the insight. Rebuild the positrak....... Hadn't thought of that. Probably better plan on that also.
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Old Apr 25, 2014 | 01:26 AM
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Originally Posted by qwank
I wish I had a 383, I still have the stock engine
ahhh sorry...thought i read that on another thread...

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