Tailshaft differences-C6?

Tailshaft differences-C6?

Jim
Jim

December 7th, 2009, 2:26 pm #1

I have a 1967 C6 that I have gone through. It's going in a 66 Fairlane. While putting the speedometer cable in, I looked at the plastic drive gears I had. The one from the 66 has 21 teeth. (I also have changed the rear from 3:25 to 3:50) The one from the 67 had 18 teeth. So I figure I'll put the 21 tooth in for now, and figure out how many teeth I need (no W. Va. jokes, please) later. Then I am thinking , I wonder if there's a difference in the tail shaft 'splines' that drive this gear.... Are the 66 and 67 shafts the same?
Regards, Jim
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I'm a rookie!
I'm a rookie!

December 7th, 2009, 6:38 pm #2

There are three different speedo counts on C6 shafts, 6, 7, 8, & 9. You probably have a 7 or 8.
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Jim
Jim

December 8th, 2009, 2:51 am #3

The 67 I am using was from a 428 Thunderbird (no idea what the rear axle ratio was) . I am not using the 66 GTA unit that was in the car, although I used the 21 spline gear .
So at this point I guess I just try it, figure at the percentage of error, and recalculate the gear tooth count? Any problem with different gears?
Regards, Jim
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Joined: May 26th, 2005, 3:00 am

December 8th, 2009, 11:40 am #4

Last edited by 65custom on December 8th, 2009, 11:43 am, edited 1 time in total.
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Jim
Jim

December 8th, 2009, 8:48 pm #5

The 67 I am using was from a 428 Thunderbird (no idea what the rear axle ratio was) . I am not using the 66 GTA unit that was in the car, although I used the 21 spline gear .
So at this point I guess I just try it, figure at the percentage of error, and recalculate the gear tooth count? Any problem with different gears?
Regards, Jim
Is it possible to see in there good enough to do this?
Thanks for those links. Once I determine tailshaft count, I can figure this out!
Regards, Jim
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Joined: May 26th, 2005, 3:00 am

December 8th, 2009, 9:24 pm #6

...or - see if you can count the output shaft revolutions per single speedo gear revolution and calculate from there based on the number of teeth on the speedo gear. I'm no expert though - just going through my first build so I'm just telling you what I would try.
Last edited by 65custom on December 8th, 2009, 9:25 pm, edited 1 time in total.
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jim
jim

December 8th, 2009, 11:13 pm #7

Is it possible to see in there good enough to do this?
Thanks for those links. Once I determine tailshaft count, I can figure this out!
Regards, Jim
.
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