4L60e - what rear end gear to go with?

Old 11-29-2009, 11:06 AM
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Jordan1984
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Default 4L60e - what rear end gear to go with?

I have a 95 impala ss with a 4L60e transmission in it. It has the stock 3.08 gear in it. Wanting to upgrade the gear, but not sure what gear I want to go with. The car will mostly be a weekend cruiser with occasional track time. I had a 350 trans with 373 gear that ran 3000 rpm at 60 mph, didnt like the motor reving that long on long stretches. Any suggestions on a good all around gear, with good take off and good street manners?
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Old 11-29-2009, 11:31 AM
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MEMRACING62
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3.42 would be middle of the road between 3.08 & 3.73. but you have to remember the 4l60 trans is overdrive & th350 is not, you wont be turning 3000 @ 60 mph with the 4l60 trans.
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Old 11-29-2009, 11:35 AM
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Jordan1984
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Yea I know that its an overdrive so the rpms would be less with a gear compared to my 350 and 373. I was thinking of 342 or 373 myself, also running the stock 17 inch rims with a 26.5 inch diameter tire.
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Old 11-29-2009, 01:14 PM
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in theory just adding the overdrive ratio of .70 you should be turning 2100 rpm. Thats without a lock up convertor clutch. if you add lock up i'll drop it about another 200-300 rpm, maybe a little more. alot of the f-body guys go with 3.73's. get down below 1500 your just going to be into the convertor stall so much it'll nuke it.
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Old 11-29-2009, 03:28 PM
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TS1955
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IMO...I would leave the 3.73's in and try it. If they are not what you like then change them.

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Old 11-29-2009, 03:35 PM
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MEMRACING62
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Originally Posted by TS1955
IMO...I would leave the 3.73's in and try it. If they are not what you like then change them.

TS1955
i WOULD AGREE
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Old 11-29-2009, 06:15 PM
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Jordan1984
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Using one of they many rear gear calculators available on the net, at 2850 rpm, with a 26.5 tire diameter, with a 3.42 gear it will cruise at 65 mph. So, ive decided to go with a 3.42 or a 3.55. Any recomendations on what gear would be better? I am planning on a 2800 stall converter and a .525/.525 LT4 hot cam conversion.
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