Speed Thingie - The 1947 - Present Chevrolet & GMC Truck Message Board Network

saxart · 03-01-2019, 08:06 PM

Does anybody know where I can get one of these speedometer converters?

Mine seems to be worn out enough that the gears don't always engage. (No speedo function.) . I'd like to find a new replacement rather than a used, possibly worn out one.

B. W. · 03-01-2019, 08:26 PM

Here's one source:

https://www.transmissioncenter.com/s...ratio-adapter/

**jocko** · 03-01-2019, 09:14 PM

$50 BIN https://www.ebay.com/itm/Stewart-War...nzx:rk:14:pf:0

$64 BIN https://www.ebay.com/itm/Stewart-War...TlC:rk:44:pf:0

$65 BIN https://www.ebay.com/itm/Stewart-War....c100005.m1851

$59 BIN https://www.ebay.com/itm/Stewart-War....c100005.m1851

Note that they have different compensation ratios, so make sure you get what you need.

**Steeveedee** · 03-01-2019, 09:34 PM

The 1.2020 is probably the ratio. I'd open it up and see if it is a reducer or speedup ratio. I'd guess speedup, since 1.2020 is greater than 1. Easy to tell- the gozinta gear will be bigger than the gozoutta gear.

**HO455** · 03-01-2019, 10:20 PM

I love technical talk.

**Canuckvetter** · 03-01-2019, 11:20 PM

Quote:

Originally Posted by B. W.

Here's one source:

https://www.transmissioncenter.com/s...ratio-adapter/

That’s where I got mine. Once installed my speedo is bang on with the GPS.

Indyuke · 11-06-2020, 02:36 PM

Resurrecting an old thread here, but I just switched from 3.73 gears to 3.08 gears and my speedometer reads slow. I need an increase of about 21%, which would mean I would need a 1:1.20 speed increase adapter, correct?

I'm also under the impression there are two types, direct drive and reverse rotation? Is that true? I'm looking for a direct drive if that's the case.

Would something like this work?

https://www.ebay.com/itm/NOS-Interna...-/353049721296

Edit: I should clarify, I've got the SM465 transmission.

**DeadheadNM** · 11-06-2020, 06:01 PM

Don't bother with a used ratio adapter. Buy a new USA made example for your application for about $100.

See my post here: http://67-72chevytrucks.com/vboard/s...&postcount=995

Edit - sorry just caught that this is a resurrected post. Yes, you need a 1.21 or so ratio.

03-01-2019, 08:06 PM	#1
saxart Registered User Join Date: Aug 2012 Location: St. Croix River Valley, WI Posts: 795	Speed Thingie Does anybody know where I can get one of these speedometer converters? Mine seems to be worn out enough that the gears don't always engage. (No speedo function.) . I'd like to find a new replacement rather than a used, possibly worn out one. __________________ Meet "Old Roy": http://67-72chevytrucks.com/vboard/s...d.php?t=707801 Last edited by saxart; 03-01-2019 at 08:15 PM.

03-01-2019, 08:26 PM	#2
B. W. Registered User Join Date: Nov 2014 Location: Bigfork, Montana Posts: 1,137	Re: Speed Thingie Here's one source: https://www.transmissioncenter.com/s...ratio-adapter/

03-01-2019, 09:14 PM	#3
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,975	Re: Speed Thingie $50 BIN https://www.ebay.com/itm/Stewart-War...nzx:rk:14:pf:0 $64 BIN https://www.ebay.com/itm/Stewart-War...TlC:rk:44:pf:0 $65 BIN https://www.ebay.com/itm/Stewart-War....c100005.m1851 $59 BIN https://www.ebay.com/itm/Stewart-War....c100005.m1851 Note that they have different compensation ratios, so make sure you get what you need.

03-01-2019, 09:34 PM	#4
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,724	Re: Speed Thingie The 1.2020 is probably the ratio. I'd open it up and see if it is a reducer or speedup ratio. I'd guess speedup, since 1.2020 is greater than 1. Easy to tell- the gozinta gear will be bigger than the gozoutta gear. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

03-01-2019, 10:20 PM	#5
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,393	Re: Speed Thingie I love technical talk. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

11-06-2020, 02:36 PM	#7
Indyuke Registered User Join Date: Feb 2008 Location: Lake Stevens, WA Posts: 623	Re: Speed Thingie Resurrecting an old thread here, but I just switched from 3.73 gears to 3.08 gears and my speedometer reads slow. I need an increase of about 21%, which would mean I would need a 1:1.20 speed increase adapter, correct? I'm also under the impression there are two types, direct drive and reverse rotation? Is that true? I'm looking for a direct drive if that's the case. Would something like this work? https://www.ebay.com/itm/NOS-Interna...-/353049721296 Edit: I should clarify, I've got the SM465 transmission. Last edited by Indyuke; 11-06-2020 at 03:22 PM. Reason: Add info

11-06-2020, 06:01 PM	#8
DeadheadNM Carpe manana Join Date: Dec 2010 Location: Eau Claire, WI Posts: 12,449	Re: Speed Thingie Don't bother with a used ratio adapter. Buy a new USA made example for your application for about $100. See my post here: http://67-72chevytrucks.com/vboard/s...&postcount=995 Edit - sorry just caught that this is a resurrected post. Yes, you need a 1.21 or so ratio. __________________ 1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 Members met: ORANGBLAZ, 2003 silverado, MikeCofield, BB72CHEVKT, Duncan&Son, Sameyrasmea72, THENEWMEXICAN, HotRod C/10, brianthelion02, Sport/Truck, ryanroo, michael bustamante, Dirt's72, Already Gone, WestButteTruck, 57taskforce, Moreyel, painterljp, AASmedic, SoCoC10, Lumaestas, carbuff382, Chevyland Last edited by DeadheadNM; 11-06-2020 at 06:08 PM. Reason: edited

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