Not sure if you’re asking for info on what gears we would suggest for your 350 trans car or are looking for vendors that sell the gears. I may be able to help for both.
I kept the 2.78 rear end that came with my car because I take it on the freeway a lot and want to conserve fuel. Of course, I put a bored out 455 in the engine bay to make sure I had enough torque to get me to highway speeds in a hurry if so desired.
You can find out what gear set is right for your type of driving by doing the math. For example, the 2.78 gets me 65 mph at 2500 RPM with 24.5 inch tires and a 4 speed. Your 350 turbo would yield approx. the same RPM at 65MPH if you have 24.5 inch tires. Of course, the down side is that I'm not as fast between lights as I would like sometimes.
I found this link a while ago that provides a calculator so you can plug in the variables and see what the affect would be by choosing different gears, tires, etc.
