mystery cat 60 cylinders

Hello, I have a cat 60 logging cruiser and it has some sort of aftermarket cylinders on it. Wondering if anyone can identify the maker of the cylinders. the maker is- I.P.&S. Co. Thanks, Caterpillarman

Here is a long shot. IPD, Industrial Parts Depot, Torrance CA. was founded in 1955, making parts for Caterpillar engines. I P & S may have stood for Industrial Parts and Supply. Did not find any relationship between the two with some quick web searches. May have been quite a few 60's around 1955 needing parts. Ed

The only other set I have seen was on the Red River logging Sixty in Willits CA. there was mention of Red River modifications for bigger cylinders before Caterpillar brought out the 6-3/4. the reinforced ribs prevent lower cylinder flange breakage.
Red River worked with Caterpillar and ESCO for patterns and steel castings This could be a company that made them for Red River?
I have also heard of Sealed Power offering 6-7/8 bore sets but have never seen a set to confirm it!