So come to find out my TH-350 trans has a BOP tail shaft with the bigger speedometer housing. So now I am trying to figure out how to find the closest gear to work for my combination. I have two gears thanks to a neighbor that owns a shop. One has 37 teeth and is a faded rose color, and the other has 44 teeth and is an olive greenish color. I have 26" tall tires and 3:31 gears. If anyone has info or links to share id appreciate it. I've been searching but so far nothing real solid coming up.
BOP
- Thread starter ChevyReb
- Start date
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It might be easier to swap the tail shaft housing with a Chevy piece.
https://www.ebay.com/itm/TH350-6-EX...133968&hash=item3431ca55bc:g:5fYAAOSwcmBfRSa5
https://www.ebay.com/itm/TH350-6-EX...133968&hash=item3431ca55bc:g:5fYAAOSwcmBfRSa5
The procedure is the same for either style gears. You can determine how far it is off right now and change one or both of the gears by that percentage. Or, you can go online and look at one of the charts that should also get you close.
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70-camaro
Veteran Member
https://www.tciauto.com/speedometer-gear-calculator
This should help with calculating the speedometer no matter what tail shaft you use.
This should help with calculating the speedometer no matter what tail shaft you use.
I saw that last night but it kept erroring no matter how I put the numbers in. It would be pretty difficult to count the gear on the output shaft without removing the tail shaft. Let me try on a screen I can see instead of my phone now.
I don't get it that site is too smart for me. No matter which field I leave blank or combo I put in it just results to "gear not available" even says that when I leave tire size blank LOL.
If anyone knows how to use it I know my tire size is 26" tall, rear gear is 3:31 to 1, and I have two driven gears, one is 37 teeth and other is 44
If anyone knows how to use it I know my tire size is 26" tall, rear gear is 3:31 to 1, and I have two driven gears, one is 37 teeth and other is 44
70-camaro
Veteran Member
If you can tell what color it is that will tells you how many teeth.
camaro71/holland
Veteran Member
You need to know the number of teeth (or the color) of the DRIVE gear and then calculate the correct driven gear.
Ok so I pulled the speedo bullet back off and made another mess. Both gears are red. Put that info in the web calculator posted above and still get no result other that gear not available. 26" tall tire 10 or 17 tooth drive gear and 37 tooth driven gear with 3:31 rear gear. No matter which one I leave blank the answer is always the same. Love to know what I'm not doing right?
