A few years ago I replaced my original 17.5:1 ratio (~4 turns) power steering gear with a rebuilt 15.25:1 (~3 turns) steering gear from Napa Auto. Relatively inexpensive compared the other stuff out there, direct bolt in. I've been very happy with it. Not sure what's available today. Would check out their rebuilt offering if looking for something more along upgraded stock. Some of the gear boxes for sale now can be very quick. Napa also has high quality hoses.

If running a taller rear axle gear consider the addition of a power steering fluid cooler. The taller gear raises engine RPM causing the hydraulic system to bypass or "return the oil" to the tank quicker building more heat.

I found the enclosed procedure years ago on the web somewhere and it works well. Also recommend the GM power steering fluid.