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C3 best rear end gear ratio.


Hagop

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I have a late 1977 c3 corvette I just bought, and it has a 383 stroker Engine

in it with 400 horsepower and a TH350 stage 1 transmission in it with I think a 456 rear gear ratio. I want to bring the RPMs down it runs at about 3500 RPMs at 70MPH. I have a 200-4R trans I want to put in it and maybe a 373 rear gear ratio. Is the 373 gear a good ratio to use for what I want to do with this Corvette. I just want to Cruz it around and try to save gas and keep the RPMs down so it does not heat up as much. Right now, when I drive on the highway it runs at 250 degrees. 

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WOW! 250* is pretty damn hot for a Gen1 block. I think that Mo has a 3.73 in her 77 with a 200R4. You will have to get with her on that though to confirm and see what RPM she runs cruising around. You will definitely drop the rpm with the overdrive gear vs a TH350 trans. I ran a 4.88 in my 66 SS Chevelle, but I was a kid and gas was only 30.9 a gallon for Sunoco 260 at the pump and didn't give a damn.:thumbs I currently run a 3.31 with a 700R4, 1850ish at 70mph.

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Hey hagop, welcome aboard. Yes,  buccaneer and mo are the people to talk to about rear ends. They both have one. Lol

mike

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I have a 383 in mine. Did drag week in it a couple weeks ago - spent a day of it climbing a mountain literally and back down at 250 miles. The temp stayed around 170-185 or so. 
250 is way not good. 

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Is this a typo? "I have a 383 in mine." It can't be the motor can it? I thought you are now running a 421 motor. 383 gear vs 373? :eek

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1 hour ago, Buccaneer said:

Is this a typo? "I have a 383 in mine." It can't be the motor can it? I thought you are now running a 421 motor. 383 gear vs 373? :eek

Holy crap Buccaneer. That’s hilarious. YES 421. I was back in my 6 months ago thoughts. I’m such a dummy. 

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3 hours ago, aenigma said:

Holy crap Buccaneer. That’s hilarious. YES 421. I was back in my 6 months ago thoughts. I’m such a dummy. 

First sign of old age. :rolf Ask me how I know. :P

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2 hours ago, Buccaneer said:

First sign of old age. :rolf Ask me how I know. :P

Hahaha I still can’t believe I did that. I think I said 383 for so many years my mind turned to mush. 

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  • 2 weeks later...
On 10/1/2023 at 9:48 AM, Buccaneer said:

Is this a typo? "I have a 383 in mine." It can't be the motor can it? I thought you are now running a 421 motor. 383 gear vs 373? :eek

Sorry I meant a 383 stroker Engine. 

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On 10/1/2023 at 11:04 AM, aenigma said:

Holy crap Buccaneer. That’s hilarious. YES 421. I was back in my 6 months ago thoughts. I’m such a dummy. 

Yes sorry I meant a 383 stroker engine. 

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1 hour ago, Hagop said:

Yes sorry I meant a 383 stroker engine. 

 

1 hour ago, Hagop said:

Yes sorry I meant a 383 stroker engine. 

He meant me. I forgot I now have a 421. It’s new to me. lol 

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