Yes it will speed up the ratio, BUT it will also increase the effort you must apply to turn. Is it a good idea, Absolutely not, thats a cast piece that takes a tremendous amount of force and welding to it will surely weaken it.

Most GM's used the same splines on the pitman arms so shop around for something that might get you were you want.

Putting a much smaller steering wheel on will have the same effect, almost!

Joe