Anyone Done this?

Heres the deal I have a big heavy power box in my car and would like to replace it with a manual box. Car is mostly street strip with skinny front tires

I have 2 manual boxes. One from a 66 charger and one I picked up at the swap meet.

I have one of the power to manual coupler on it's way.

Question I have is where would be the best place to find a pitman arm for my f body and the nut/ washer for the pitman arm.

I know firm feel has some fast ratio arms. But Im just looking for like a moog pitman arm or something along those lines

Any help would be great

Thanks

Phil