700 Lock Up RPM

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Dec 30, 2024 | 02:33 PM

Brown Bandit

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700 Lock Up RPM

I have a 82 corvette that i just did the crossfire to carb conversion. It has the stock 700r4 and stock 3:07 gears and I used the Painless lock-up kit to get it into overdrive. Also stock tire size too. At about 40 mph it goes into overdrive and goes from 1500 rpm down to 1000 rpm which is great. My question is at 60 to 70 mph what should the rpm range be? Im getting around 1500 to 1600 rpm around 60 to 70 mph. Is that normal cause i think thats pretty damn good. I know the tach is working properly and just wanted to see if this sounds right. Thanks.

Dec 30, 2024 | 03:29 PM

Eric P

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I thought 82's had a 2.87 rear gear ?

Dec 30, 2024 | 04:07 PM

Brown Bandit

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Quote:

Originally Posted by Eric P

I thought 82's had a 2.87 rear gear ?

I thought they were 3.07. Regardless 2.87 or 3.07, does 1500 rpm sound about right at highway cruising around 60 to 70 rpm? What are your thoughts?

Dec 30, 2024 | 04:22 PM

Piersonpie

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From: Minnesota

Multiplying that 2,483 by .7 for your overdrive gear gives you 1,738 RPM. Doing the same equation with a 2.87 rear end gives you 1,625.

Dec 30, 2024 | 04:23 PM

71 Vert LS1

Melting Slicks

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Just a thought.
On my LS swaps with 4L60E's I have the ecm programmed to engage 4th gear along with lock up at about 45-50 mph. The reason I do that is because around here many of our local roads that we cruise in the summer have 40 mph limits. Locking up 4th and the converter can lug the engine at low mph.

Dec 30, 2024 | 05:49 PM

Fly skids up!

Melting Slicks

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From: Fleming Island, FL

Your tachometer must be off by quite a bit.

Dec 30, 2024 | 08:52 PM

1860army

Burning Brakes

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From: Central NJ

82's came with either 2:72 or 2:87 rears, the CEs had 2:87. Not sure about the exact RPMs but its higher @70

60

Dec 30, 2024 | 09:11 PM

lars

Tech Contributor

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From: At my Bar drinking and wrenching in Lafayette Colorado

Quote:

Originally Posted by Brown Bandit

Im getting around 1500 to 1600 rpm around 60 to 70 mph. Is that normal cause i think thats pretty damn good.

My '85 C4 with the same setup would pull about 1700 rpm at 65-70 mph, giving me 26-28 mpg at steady-state highway cruise with the Multiport fuel injection.