alum. i-beam
Aluminum technology wasn't all that good back then in a cost effective manner like today. While I don't know which alloy would want to use if you were to fabricate a set. I do know you have to realize Aluminum has a fatigue 1/2 life. Where as steel never fatiques when used according to its effective design.
I know Ford and GM are using cast aluminum A-arms these days, but these are throughly designed pieces with proper alloys. Also how would you bend a aluminum I beam? Aluminum does not like to be bent at all.
If you want it shiney like aluminum you can have them nickel plated, and or powder coated in a aluminum colour.



