Overall gear ratio for a 4x4 gaser November 22, 2009 05:38AM
Im building a new drivetrain 4 my truck this winter and sum guys tell me that the overall drive ratio should be around 30 to 1. But everyone is running a big block, and im going with a small block any advice would very helpfull!
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Re: Overall gear ratio for a 4x4 gaser November 24, 2009 06:40AM
The final drive ratio you can pull depends on a few factors. Horspower/Torque, transmission, tires and how well your chassis puts all this to the ground. That said a 30:1 final is to slow IF you have the motor to pull a faster gear, if not, get one if you want to be competitive. Also, dollar for dollar, a big block is the better way to go IMHO
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Re: Overall gear ratio for a 4x4 gaser November 24, 2009 12:12PM
I have a 408 sbc with about 600 hp ,and about 585 tq and im gona run a street legal class. im thinkin about running an automatic turbo 400 dont have a t-case picked out yeat, Ive been talkin with some guys at Off Road Design about that! Im just wondering how much horse power and rpm its gona take to keep up with them? Im all new to 4x4 pulling, Tires are 33 12.5s But i can change that also. Just dont know whare to start on a overall gear ratio. I could some advice! Thanks!
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Re: Overall gear ratio for a 4x4 gaser November 24, 2009 02:35PM
At what RPM is it making those numbers and are they dyno numbers? Also, where 'bouts are you from and is there an organization y'all run with? And finally, you'll get a lot more help over on Reddogs forum when it comes to truck pulling. Nothing against the fine upstanding men and women on this forum, but for the most part, they know tractor pulling much better than truck pulling.
Stop on over to Reddog. [www.network54.com]



Edited 1 time(s). Last edit at 11/24/2009 02:36PM by HorsinAround.
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Re: Overall gear ratio for a 4x4 gaser November 27, 2009 10:48AM
Im running 28.98:1 with an auto and 33's and its way to low. My engine screams but I have no wheel speed which mean no momentum and thats what wins a truck pull. The faster the sleds moving the further it goes when the box tops out. With 33's 25:1 should be about right. As far as T cases go this is just my oppinion but stay away from the aluminum cases with planitary low range. They are geared to low. Most newer cases have a 2.72:1 low. The np208 that GM used had a 2.61:1. Find a np205. They have a 1.96:1 low. A TH400 (2.46:1), NP205(1.96:1), and 5.13:1 axle gearing will give you 24.72:1. This is a comon set up for pro stock/ street mod trucks. If you use a T case with a 2.72:1 and a TH400 you only need 3.73:1s to get 24.95:1. I know alot off trucks with big blocks running at about 25:1 with 35's or even 36's. Your small block and 33's should work good. Then what the hell do I know Im still screaming and going nowhere.
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Re: Overall gear ratio for a 4x4 gaser thanks November 28, 2009 09:46AM
Thanks
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