I am switching over to 3.73 in my 9-bolt, it was 3.27, and I am wondering if there is a company that makes a new speedo gear for the transmission, 700R4 in a 87 gta, so my speedometer won't be off? I hope you guys can direct me in the right direction.

 

go to www.700r4.com , they have a calculator that you can use to find out the gears that you need, they can be picked up at a GM dealer for about 5 bucks each. I went to 3.73 gears with 215/65/15 tires and needed a 15/43 combo.

 

Thanks I appreciate it. I hope that helps me out.