what rear gear to run

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Hyperballsmcgee

Hyperballsmcgee

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hey fabo, putting together an 8.75 rear for my scamp, its currently got a 340/904.
not sure exactly how tall of a tire i have but i'll upload a pic for a general idea.

right now it has a 7.25 with a 2.76 gear, its still pretty fast compared to the average vehicle, but i know a ring and pinion make all the difference in the world, the car pretty much only drives around town, so i'm thinkin' i should go with like a 3.92. i want something that's quick when you stomp the pedal, y'know? i had a set of 4.10's but thats a little steep for me i think.
 
Hyperballsmcgee said:
hey fabo, putting together an 8.75 rear for my scamp, its currently got a 340/904.
not sure exactly how tall of a tire i have but i'll upload a pic for a general idea.

right now it has a 7.25 with a 2.76 gear, its still pretty fast compared to the average vehicle, but i know a ring and pinion make all the difference in the world, the car pretty much only drives around town, so i'm thinkin' i should go with like a 3.92. i want something that's quick when you stomp the pedal, y'know? i had a set of 4.10's but thats a little steep for me i think.
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depends on a lot of factors, what convertor you running , what camshaft/intake (RPM range). what kind of driving you do on the street/hwy.
 
We always considered 3.23 a good "all around" gear for a basically stock 340 A body. 3.91 is as low a gear I'd use in a mostly street car. You can adjust either way depending on what you can take personally. I had 4.10 gears for a month or two, then sold them. The nice thing about the 8 3/4 is it only takes an hour to change gears, if you are slow. I have almost everything from 2.76 to 3.91 and 4.56.
 
driving this car i tend to have a lead foot... stock converter, i dont know exact specs on cam, i'd say its something short lift long duration, intake is an edelbrock high rise.
 
i'm interested in the 3.91 if you're selling it. i have a 3.23 center section already but i plan on using that only if the car has to take a long trip say to bowling green or something, but rarely does it see highway use.
 
3.55 is all around good. But if it's just in town with no hiway go 3.91 or 4.10 if you want max acceleration.
 
My understanding is that you probably want the quickest gear you can use with your tire size that will still leave you in a usable power range rpm wise when you go into passing gear from a steady highway cruise. That is, if you cruise it on the highway. There are maths around somewhere to figure out rpm at what speed with what tire and what gear.
 
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