Power to Manual Steering Conversion - 1970 Plymouth Big Block Duster Project

In order to pick up some much needed clearance between the blower drive and radiator, I ditched the power steering in favor of a manual box. This allowed me to eliminate 1 V-Pulley off the front of the motor and gain .75".

I considered a used box but decided to go with a rebuild and found a good deal through Car Steering Wholesale (via a deal/sale on ebay) for well under $200 including shipping.

When it arrived I pulled my old pitman arm (using a puller, some heat, and persuasion) and transferred it to the 'new' box. With an aluminum case, it's significantly lighter and physically smaller than the power chuck.

I knew going into this conversion that my power steering column would be too short so I turned to Firm Feel for their power to manual conversion adapter. It makes up the difference in length and also the larger input splines found on the manual box.

By the way, Flaming River makes a u-joint style conversion for these types of swaps too.

Firm Feel has a solid reputation for quality products but for whatever reason their adaptor fit loosely on my box. (You can view the sample video I sent to Firm Feel here). Either the box was at fault or the tolerances on the adaptor were off. I later came to the conclusion that the box was fine.

Firm Feel was very good about working with me and sent another adapter to try. However, the result was the same.

Time to go to plan B. I got lucky and found a manual steering coupler on ebay. The seller wasn't far from me so it arrived quickly.

The manual coupler was in pretty rough shape when it arrived with rust and pitting. A soak in Evaporust cleaned it up and, despite it's condition, it fit on the box much better than the Firm Feel adapter. There was no slop whatsoever.

I had an extra power steering shaft on the shelf so I cut the end off and added a 2.5" piece of solid .75" round stock.

Beveling the ends of the cuts allowed for good weld penetration. I used angle iron and clamps to keep the pieces aligned and straight.

Here's a side by side comparison to the PS shaft and coupler with Firm Feel adapter and the welded shaft and manual coupler.

I had a coupler rebuild kit sitting on the shelf (Dorman "Steering shaft rebuild kit" # 425-253). You can get the kits through your local auto parts store at about half the price of what some guys are selling them for online. And as far as I can tell, the parts are exactly the same.