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Re: [oletrucks] Gear Ratio wisdom sought

To: "BORDER,RYAN \(HP-FtCollins,ex1\)" <ryan_border@hp.com>,
Subject: Re: [oletrucks] Gear Ratio wisdom sought
From: "Connie Dodd" <cwdodd1@home.com>
Date: Fri, 15 Dec 2000 19:13:00 -0500
Where can you get a new ring and pinion for $100 ?????

C W Dodd
56-3200
Greenville SC



----- Original Message -----
From: "BORDER,RYAN (HP-FtCollins,ex1)" <ryan_border@hp.com>
To: <oletrucks@autox.team.net>
Sent: Friday, December 15, 2000 3:48 PM
Subject: [oletrucks] Gear Ratio wisdom sought


> In brief, I need to select the gear ratio for my rear axle, and am hoping
to
> tap some of your collective wisdom.
>
> 55 Task Force
> Mildly tweaked 350cid (Headers, Manifold, Cam, etc.)
> TH-350 3spd tranny, 1:1 3rd gear
> Building for 30.9" Diameter rear tires
>
> Churning my calculator, I've come up with a magic number of 761.5: to
> convert a Gear Ratio to 70mph engine rpm's.  For instance, 3.50 gears
should
> give me (3.5*761.5) 2665rpm at 70mph.
>
> Now, I just need to figure out what I'd like my highway cruising rpm to
be,
> and I'll be ready to buy a ring and pinion.
>
> One one hand, a low gear ratio would definitely be a benefit at cruising
> speed.
> On the other hand, the truck will see a lot more in-town use than highway
> use, and just for grins, it would be nice to have a little snap off the
> line.
>
> Yeah, I know, in the perfect world I'd change to a 4-speed overdrive
tranny
> and have the best of both worlds ;-).  Then again, I could also put a
blown
> big-block in it... in either case, if I one day decide to persue either of
> those options, I'll probably be able to spend $100 on a new ring and
pinion
> gear to match.  So, for now, I'm focusing on how to optimize for what I
> have.
>
> Given my setup, what would you guys recommend as a good compromise?  Some
> possible alternatives:
>
> ratio 70mph
> 2.50 1900rpm What my rear end has in it now
> 3.00 2280rpm
> 3.25 2475rpm
> 3.50 2665rpm Common F-150 ratio
> 4.11 3129rpm Conventional street/strip gears
>
> What would you do??
>
> Ryan.
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

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