rmarks 20 Report post Posted April 3, 2016 How may teeth are on a speedo gear for a 4 speed wide-ratio tranny, 18, 19? Quote Share this post Link to post Share on other sites
fvike 173 Report post Posted April 3, 2016 Depends on your rear axle ratio. Also, if your tire height differs from stock, it will have an impact. Perhaps this TCI calculator or this GTSparkplugs calculator can help. Quote Share this post Link to post Share on other sites
jrw69 16 Report post Posted April 3, 2016 My Mach1 4 speed toploader with 300:1 rear end has a 19 tooth gear and is very accurate. I am running 15" wheels. TCI Calculator is a help but you may have to experiment with gear. Be sure to get the genuine Ford gear. They last and don't get chewed up. JRW69 Quote Share this post Link to post Share on other sites
Mach1 Driver 560 Report post Posted April 3, 2016 with 300:1 rear end Wow! Sorry I couldn't resist ;) Quote Share this post Link to post Share on other sites
jrw69 16 Report post Posted April 3, 2016 Sorry Mach 1 Driver. Never had good typing skills. JRW69 Quote Share this post Link to post Share on other sites
skidmarky 50 Report post Posted April 4, 2016 https://www.428cobrajet.org/speedo-calc Quote Share this post Link to post Share on other sites
