Hi I have the same question, as what colour of gear, I have the 2.78 ratio and stock tire size, I am putting this car together from pieces so do not know what colour the original one was, 70 442 with 350 turbo, Yes i know not original, i could order the whole kit but would prefer to just get one gear. Thank for the help in advance.

 

Go to 5speeds.com he has a chart for tire size, gear ratio and gear

 

Here's your own thread on the subject. The easiest way to find out is to simply look in the 1970 Chassis Service Manual or PIM. There is a speedo gear chart for each trans, available gear ratio, and available tire size. The trans doesn't know if it's in a 442 or a Cutlass. The "stock size" tire is a bias ply G70x14 - is that what you REALLY have? And since the trans isn't original, we can only ASSUME the speedo drive gear in the trans is 18 tooth. Assuming all this, the correct speedo gear for 2.78 rear gears and G70x14 tires is a brown 39 tooth gear.

 

Are you looking drive or driven?