To expand a little on what has already been written on this topic...
I did a lot of research on running boards when I was about ready for some for my '39 Plym. I found that the best way to go was with NEW BOARDS from Buckeye...
They make a whole new board which is close to the original board only made a little stronger, they then mold a new rubber coating over the new metal base which is so close to the originals, that I defy any one to find fault with the product.  I have personally recommended Buckeye to several people, who were all very pleased.

You can try to use your old boards, cleaning them up and shipping them to Buckeye, they in turn will vulconize new rubber covers onto you board. The down side of using your old boards is that you have to expend the labor to get them new metal clean, then you have to ship them to Buckeye..... all of this to save about $50.00 and still have running boards that are almost seventy years old.  >:( ....Bill

Hello,

Go to Buckeye Rubber Co. (www.hotrodssuperstore.com) I used them recently for my 1939 plymouth. They did an excellent job. You will be mor than pleased.

Bert,

Buckeye rubber did mine and they look great

Mike

 try   www.automotiverubber.com, they do moulded running board covers but i don't know if they do 39 Plymouths.

Hello Everyone.? I have a '39 p8 four door sedan and would like to recover the running boards. They were covered once already but are not correct and are showing wear and rips, problem is I don't know where to look for covering material. Any sugestions would  help. Thanks.