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Old 07-28-2021, 07:03 PM   #1
Canuckvetter
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4000RPM tach read on an 8000RPM lens

Making a 4000RPM mechanical tachometer read 8000 RPM with a 50% gear reduction at the distributor. Iím going to re-do the red line to read 5500 RPM

https://67-72chevytrucks.com/vboard/...1&d=1627513183
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1967 Oshawa built LWB Fleetside. 327,3 OTT, 515 Vermilion, Fawn interior. 04/2015
1967 Oshawa built LWB Fleetside. 327 Auto, 545 Ver/Off-White, Fawn , CST, A85 belts, K31 throttle. 01/2018
1967 Oshawa built Panel,K10, 283/4spd,505 Green, Fawn interior, F&R positrac axels, 1 of 30 built.03/2020
1967 Oshawa built LWB Fleetside, 250 Auto, 511 Aqua, Custom, Step bumper. 09/2020
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Old 07-28-2021, 07:39 PM   #2
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Re: 4000RPM tach read on an 8000RPM lens

Hmm,

Kinda cool thinking there. Sounds logical, like it should work.

Did all 67-72 tachs operate mechanically? Or would that be from heavy duty truck class such as 1 ton and up?


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Old 07-29-2021, 12:22 AM   #3
Canuckvetter
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Re: 4000RPM tach read on an 8000RPM lens

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Originally Posted by HotWheelsFan View Post
Hmm,

Kinda cool thinking there. Sounds logical, like it should work.

Did all 67-72 tachs operate mechanically? Or would that be from heavy duty truck class such as 1 ton and up?


Bob
67-72 C50 or C60 Diesel truck
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1967 Oshawa built LWB Fleetside. 327,3 OTT, 515 Vermilion, Fawn interior. 04/2015
1967 Oshawa built LWB Fleetside. 327 Auto, 545 Ver/Off-White, Fawn , CST, A85 belts, K31 throttle. 01/2018
1967 Oshawa built Panel,K10, 283/4spd,505 Green, Fawn interior, F&R positrac axels, 1 of 30 built.03/2020
1967 Oshawa built LWB Fleetside, 250 Auto, 511 Aqua, Custom, Step bumper. 09/2020
Members who I have met personally. Metaldoc, chevnkevin, 62 Longbed, 72LHorn, 72MARIO, YBNORML, TBONE1964, Classic Bowties, Chevemall.
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Old 07-29-2021, 01:42 AM   #4
chewychevy67
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Re: 4000RPM tach read on an 8000RPM lens

I'm interested to see how it all looks finished in the cluster. Good idea. I never thought of the reduction when I did mine.
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Old 07-29-2021, 10:04 PM   #5
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Re: 4000RPM tach read on an 8000RPM lens

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Originally Posted by chewychevy67 View Post
I'm interested to see how it all looks finished in the cluster. Good idea. I never thought of the reduction when I did mine.
4000 to 8000 was easy 50% reduction
4000 to 5000 is above my pay grade to figure out lol. 12.5% reduction I think.
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1967 Oshawa built LWB Fleetside. 327,3 OTT, 515 Vermilion, Fawn interior. 04/2015
1967 Oshawa built LWB Fleetside. 327 Auto, 545 Ver/Off-White, Fawn , CST, A85 belts, K31 throttle. 01/2018
1967 Oshawa built Panel,K10, 283/4spd,505 Green, Fawn interior, F&R positrac axels, 1 of 30 built.03/2020
1967 Oshawa built LWB Fleetside, 250 Auto, 511 Aqua, Custom, Step bumper. 09/2020
Members who I have met personally. Metaldoc, chevnkevin, 62 Longbed, 72LHorn, 72MARIO, YBNORML, TBONE1964, Classic Bowties, Chevemall.
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Old 07-30-2021, 12:15 PM   #6
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Re: 4000RPM tach read on an 8000RPM lens

Quote:
Originally Posted by Canuckvetter View Post
4000 to 8000 was easy 50% reduction
4000 to 5000 is above my pay grade to figure out lol. 12.5% reduction I think.
20% reduction. My apologies - Iím slightly OCD.
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Old 07-31-2021, 06:23 AM   #7
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Re: 4000RPM tach read on an 8000RPM lens

Quote:
Originally Posted by Canuckvetter View Post
4000 to 8000 was easy 50% reduction
4000 to 5000 is above my pay grade to figure out lol. 12.5% reduction I think.
I'd trade you a nice gas tach cluster if ya wanted.
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1972 Chevy Longhorn K30 Cheyenne Super, 359 Inline 6 cylinder, Auto Trans, Tilt, Diesel Tach/Vach, Buckets, Rare Rear 4-link and air ride option Build Thread
1972 C10 Suburban Custom Deluxe
1969 Chevy milk truck
1971 Camaro RS 5.3 BTR STG3 Cam Super T10
1940 Ford 354 Hemi 46RH Ford 9" on air ride huge project


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Old 08-01-2021, 12:03 AM   #8
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Re: 4000RPM tach read on an 8000RPM lens

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Originally Posted by Dieselwrencher View Post
I'd trade you a nice gas tach cluster if ya wanted.
Thanks for the sweet offer lol. Iím looking forward to getting the mechanical one revved up lol!
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1967 Oshawa built LWB Fleetside. 327,3 OTT, 515 Vermilion, Fawn interior. 04/2015
1967 Oshawa built LWB Fleetside. 327 Auto, 545 Ver/Off-White, Fawn , CST, A85 belts, K31 throttle. 01/2018
1967 Oshawa built Panel,K10, 283/4spd,505 Green, Fawn interior, F&R positrac axels, 1 of 30 built.03/2020
1967 Oshawa built LWB Fleetside, 250 Auto, 511 Aqua, Custom, Step bumper. 09/2020
Members who I have met personally. Metaldoc, chevnkevin, 62 Longbed, 72LHorn, 72MARIO, YBNORML, TBONE1964, Classic Bowties, Chevemall.
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Old 08-20-2021, 11:04 PM   #9
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Re: 4000RPM tach read on an 8000RPM lens

A mock up of the lens & mechanical tach in the cluster. I have the vacuum gauge in the truck now. I may convert this cluster to accommodate a clock. The finished cluster likely wonít go in the truck till the winter when I install the L79 intake and tach drive distributor. So far Iím happy with how it has turned out.






https://67-72chevytrucks.com/vboard/...1&d=1629514543
https://67-72chevytrucks.com/vboard/...1&d=1629514565
https://67-72chevytrucks.com/vboard/...1&d=1629514585
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1967 Oshawa built LWB Fleetside. 327,3 OTT, 515 Vermilion, Fawn interior. 04/2015
1967 Oshawa built LWB Fleetside. 327 Auto, 545 Ver/Off-White, Fawn , CST, A85 belts, K31 throttle. 01/2018
1967 Oshawa built Panel,K10, 283/4spd,505 Green, Fawn interior, F&R positrac axels, 1 of 30 built.03/2020
1967 Oshawa built LWB Fleetside, 250 Auto, 511 Aqua, Custom, Step bumper. 09/2020
Members who I have met personally. Metaldoc, chevnkevin, 62 Longbed, 72LHorn, 72MARIO, YBNORML, TBONE1964, Classic Bowties, Chevemall.
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Old 08-20-2021, 11:10 PM   #10
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Re: 4000RPM tach read on an 8000RPM lens

https://67-72chevytrucks.com/vboard/...1&d=1629515382
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__________________
1967 Oshawa built LWB Fleetside. 327,3 OTT, 515 Vermilion, Fawn interior. 04/2015
1967 Oshawa built LWB Fleetside. 327 Auto, 545 Ver/Off-White, Fawn , CST, A85 belts, K31 throttle. 01/2018
1967 Oshawa built Panel,K10, 283/4spd,505 Green, Fawn interior, F&R positrac axels, 1 of 30 built.03/2020
1967 Oshawa built LWB Fleetside, 250 Auto, 511 Aqua, Custom, Step bumper. 09/2020
Members who I have met personally. Metaldoc, chevnkevin, 62 Longbed, 72LHorn, 72MARIO, YBNORML, TBONE1964, Classic Bowties, Chevemall.
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Old 08-21-2021, 05:22 AM   #11
Dieselwrencher
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Re: 4000RPM tach read on an 8000RPM lens

It's looking very nice!
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1972 Chevy Longhorn K30 Cheyenne Super, 359 Inline 6 cylinder, Auto Trans, Tilt, Diesel Tach/Vach, Buckets, Rare Rear 4-link and air ride option Build Thread
1972 C10 Suburban Custom Deluxe
1969 Chevy milk truck
1971 Camaro RS 5.3 BTR STG3 Cam Super T10
1940 Ford 354 Hemi 46RH Ford 9" on air ride huge project


Tired of spark plugs? Check this out.
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Old 08-21-2021, 12:33 PM   #12
chewychevy67
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Re: 4000RPM tach read on an 8000RPM lens

Looks cool. I like it
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