For a number of reasons I want to replace this pipe with a red or white oak post, 2"x3". The 3" dimemsion is in the fore and aft position and one side of the post will be supported by a structural bulkhead which should alleviate any concerns about column failure in the side to side direction.

I don't know the loads involved but they are not eccentric and I do have the original specs that specified the aluminum pipe (it lasted 40+ years. So, What I would like to know is the compressive strength of the two struts, and the unsupported, non eccentric load column strengths of the 1 1/4" "standard" aluminum pipe and the 2"x3" oak post. Thanks