Author Topic: Rear end gear change  (Read 5101 times)

Offline 1986_CHEVY_454

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Rear end gear change
« on: May 12, 2012, 04:09:30 pm »
I have a 1986 c30 with a 454 and i believe that it has a 4.10 ratio in the rear end. Ive been told that if i change that i will get better gas mileage and it will be a little faster. Just wondering what gear ratio i should change to. i don't tow anything with this vehicle it just drive it on the weekends mostly.

Offline VileZambonie

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Re: Rear end gear change
« Reply #1 on: May 12, 2012, 04:12:07 pm »
What are you looking for? Better highway mileage? If you're looking for better around town mileage you're thinking backwards.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline 1986_CHEVY_454

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Re: Rear end gear change
« Reply #2 on: May 12, 2012, 04:14:53 pm »
Im thinking more highway, i dont travel through the city to often. and im really looking to pick up some speed to. ive seen stuff about i think it was 3.21 ratio but i could be wrong.

Offline VileZambonie

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Re: Rear end gear change
« Reply #3 on: May 12, 2012, 04:21:34 pm »
What trans do you have?
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline 1986_CHEVY_454

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Re: Rear end gear change
« Reply #4 on: May 12, 2012, 04:24:37 pm »
its 3 speed 400. im trying to get some speed to make it a nice street or strip truck. and gas mileage would be great too. hopefully something better then 8 mpg

Offline VileZambonie

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Re: Rear end gear change
« Reply #5 on: May 12, 2012, 04:27:13 pm »
4L80E is the only way you would really improve both performance and economy. I would be against changing the final drive ratio
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              ⌠ŻŻŻŻŻ'   [☼===☼]
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline 1986_CHEVY_454

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Re: Rear end gear change
« Reply #6 on: May 12, 2012, 04:28:53 pm »
alright thank you. but do you have any suggestions on what gears would help the performace, instead of towing.

Offline VileZambonie

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Re: Rear end gear change
« Reply #7 on: May 12, 2012, 04:30:45 pm »
You have the perfect performance ratio already. Going the other way is going to turn your truck into a slug.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline 1986_CHEVY_454

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Re: Rear end gear change
« Reply #8 on: May 12, 2012, 04:33:06 pm »
Oh thats good to hear. I guess that sves money for new carb and intake manifold. And Thanks for the help!!