Modified idler arm?

hey guys. i have a 67 dart with a 68 k-member. car is big block with 73+ a body disc conversion. I have less then 1k miles on the car and my brand new idler arm is ****. it has a ton of play in it. the play is in the body of the arm. where the mounting bolt passes thru. I have read that the newer arms are built with plastic internals and the headers melt them? I will be pulling mine soon. anyone ever take one apart and looked at what going on inside? why couldn't i gut the housing and have the housing machined to install a bearing on top and bottom? then the correct spacers needed to put it in stock location in the k-member?