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View Full Version : What Gear Ratio?


InMotionJosh
03-05-2007, 06:50 PM
I am needing to order my new currie 9 inch for my 70 chevelle but am not sure which gears to go with. I am going to be running either a 408 or 427 LSX motor N/A. Its going to be backed with a 4l80e transmission. I need to figure out what gear ratio to order though. I plan to use a 28 inch tire and would like this car to be good on the highway and on the street. Id like a good balance of performance for both. i was thinking maybe a 3.42 or 3.55 would be a nice choice. Any thoughts?

ProdigyCustoms
03-05-2007, 07:01 PM
We sell a bunch of Moser rears and use a lot of 3.50 gears in Fords. You can also get away with a 3.70 gear and get a little more snap out of the hole and only give up a little bit of RPM on the Hwy.

The 9" is a good rear end, but have you though about a 12 bolt? For the same money you can have a 33 spline True Trac 12 bolt with a performance cover that is stronger then a 31 spline True trac 9" and the 12 bolt does not steal horsepower. Were selling more and more 12 bolts since the 33 spline True Tracs came out.

InMotionJosh
03-05-2007, 07:03 PM
I have not really looked into a 12 bolt at all. You say it uses less power than a 9 inch? I think the car is going to have traction problems on the street anyway so too much snap out of the hole wont be helping much.

PM me with a price for a fully built bolt in 12 bolt for a 70 chevelle with gears etc....im in the market ASAP!

chicane
03-05-2007, 07:16 PM
I say 3.70's (or 3.73's for the 12 bolt) with a 28" tire.

pdq67
04-02-2007, 09:53 PM
He, He!!

Imho, a Chevelle need's a GM 12-bolt under her and I bet that you would dearly love the 3.31's IF you can find a good used set, otherwise use 3.42's!!!

And again, imho, no lower than 3.73's!!

That said, a 9" w/ 3.50's should do you well.

pdq67