We had six '55 Chevy COE fire engines and all came with the Buick nailhead 322's in them from the factory and they did have Power Steering. When we'd get parts we'd use the Factory Shop manual and order from our local Parts supplier. I did note that more than once his supplier was getting those parts from a Buick dealer in an adjacent large town. We ran those rigs for years and they did hold their own. When the 348 truck engines showed in 1958 we got two of those also. The '55's would run the legs off those GM truck version 348's.
Normbc9