i have a '67 with a t-5 with the stock rearend, my guess its a 3.00:1 or somewhere around there. i got a 23 tooth speedo gear that is made for a 3.55 rearend. with the new gear, my speedo reads 50mph when im going about 70mph. i want to try another gear but im not sure if i should go with a 20 tooth or an 18 tooth? the speedo is way off so i was thinking an 18 tooth might get it close enough. i'm just trying to get it close for now, doesnt have to be perfect. i'll be using the 23 tooth speedo gear when i swap out my rearend for a 3.55, so it wasnt a waste. what speedo gears are you guys using for your t-5's with a stock rearend? any help would be great! thanks!