Switching to Manual Steering

Nothing to it. Need a manual steering box, and a pitman for your style of car. Usually it's '72 and down, and '73 and up for pitman arms on A bodies.
You can buy this adaptor MOPAR Steering Column ADAPTER PS to Manual A-Body Plymouth Dodge Duster Demon GT | eBay
Or you can lock a grip pliers on your lower column and pound it down till it fits. I've done it both ways. If you don't mind the money, the adaptor is easier.
you will loose 40 lbs, a belt, and enjoy the extra room around header/exhaust manifold and around the front of the motor!