I have searched far and wide and the lowest I could find was 10 tooth, which would leave me with a 5.4:1 ratio. How much acceleration would that knock off, and could it damage the torque converter?
The 10t will be the smallest you will find for 3/4" jackshaft.
I think you will be just fine with that 7" driven, 5.4:1 gear, and those small 14" tires. Your final drive will be around 6.04:1 on the high side. On the low side it'll be around 16.2:1- 17.01:1. I got a feeling you'll be shopping for new rear tires in the near future.
I would recommend when you get the 7" driven, while its still new and easy to get apart and put back together, jus go ahead and move the spring to the hole farthest left, if looking at holes at the 12 o'clock position. This will hold low gear jus a tad bit longer, allowing the engine to build power before shifting into high to quickly. It won't lug the engine down so fast.
Change out 1 plain driver spring for 1 white driver spring. The stock springs and weights will engage the belt at 2200 rpm. 1 white and 1 plain will engage at 2600 rpm, this is a perfect engagement rpm for a stock governored engine on a go kart. That stock engine peaks torq around 3000-3200, so getting it up near peak torq, before engagement, will help it pull weight outta the hole. It'll also put a big smile on your face.
Good luck, keep updating you progress, you are going in the right direction.
