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Author Topic: spedo gear ?  (Read 2704 times)

Offline necromonger

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spedo gear ?
« on: July 28, 2013, 02:00:29 pm »
what color spedo gear do I need for 16 inch tires trans is a sm465.
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new build,1978 chevy 3/4 ton 2 wheel drive 350 4 speed trans.

Offline Irish_Alley

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Re: spedo gear ?
« Reply #1 on: July 28, 2013, 04:16:19 pm »
16" rims? What gear ratio do you have
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If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline necromonger

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Re: spedo gear ?
« Reply #2 on: July 29, 2013, 07:14:34 am »
I will pull the pan and let you know.because I don't have a clue.
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new build,1978 chevy 3/4 ton 2 wheel drive 350 4 speed trans.

Offline Irish_Alley

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Re: spedo gear ?
« Reply #3 on: July 29, 2013, 07:57:03 am »
You said 16" tires but that don't sound right. What's the numbers on the tire
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If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline necromonger

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Re: spedo gear ?
« Reply #4 on: July 29, 2013, 06:19:46 pm »
235/70/16
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new build,1978 chevy 3/4 ton 2 wheel drive 350 4 speed trans.

Offline necromonger

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Re: spedo gear ?
« Reply #5 on: July 29, 2013, 06:20:39 pm »
rear is a 3.73
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new build,1978 chevy 3/4 ton 2 wheel drive 350 4 speed trans.

Offline rich weyand

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Re: spedo gear ?
« Reply #6 on: July 29, 2013, 08:44:13 pm »
The original tires on the 1978 K-30, per the chevy brochure, were 31x9.50x16.5.  That's a 31" tire.  The 235-70R16 is a 29" tire.  Your speedometer right now with the shorter tires should read 31/29 high, or about 7% faster than you are really going.

That assumes the rear-end ratio was not changed since new.  3.73:1 sounds like the stock ratio. 

Not sure which speedo gear is in there now, so hard to tell you which one to switch to.
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Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift
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