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| | | | Joined: Oct 2011 Posts: 36 Wrench Fetcher | | Wrench Fetcher Joined: Oct 2011 Posts: 36 | I have the sm420 granny gear transmission in my 51 and would like to know if there were different speedo driven gear tooth counts for that transmission. Mine is a 14 count tooth and I saw one for sale on ebay that was a 12 tooth, supposedly for the same transmission.
I am looking to buy one.
Last edited by bucketlist51; 02/16/2016 11:05 PM.
| | | | | Joined: Jan 2001 Posts: 5,337 'Bolter | | 'Bolter Joined: Jan 2001 Posts: 5,337 | Depending on tire size and axle ratios several speedo gear ratios were used on SM420s.
The parts book shows 4 tooth drive and 12 tooth driven for 1948-54 with 4.11 diff.
Last edited by Pre '68 Dave; 02/16/2016 11:32 PM.
See the USA in your vintage Chevrolet! My Blog | | | | | Joined: Jan 2010 Posts: 4,263 Shop Shark | | Shop Shark Joined: Jan 2010 Posts: 4,263 | 52-53 had 0-90 speedo
Not sure if that will effect your ebay search | | | | | Joined: Oct 2011 Posts: 36 Wrench Fetcher | | Wrench Fetcher Joined: Oct 2011 Posts: 36 | | | | | | Joined: Jan 2010 Posts: 378 Shop Shark | | Shop Shark Joined: Jan 2010 Posts: 378 | I have a 1949 with a 4-speed (SM-420) out of a 1951 3/4 ton and a rear gear with 3:90 ratio. open drive shaft, but I don' see where that matters but I would sure like to know about what I need also. I did not intend to take your post over just seems like a good place to find out what I need. Thanks Steven | | |
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