Milling ex manifold Question

these are the large outlet manifolds & I have both of em. this is a dirt track stock car & I will be taking the inner fenders out & I started on that close to the UCA cam bolt supports on the pass side which gained me some additional space & I slotted the manual steering box mounting holes so I could lower it a bit which gained me some (I hope that doesn't mess up the steering geometry). On the dr side it is a thin steel shaft & not the OE column so that helps. I'm thinking that maybe I can shift everything over to the dr side a bit more. I am going to make it over there today & I will measure the flange thickness of the good 340 pass side mani that I have (though its overall width is way wider than these magnums cuz I tried it) & also go to a machine shop though one shop did me that it cannot be done cuz the outlet flange is in the same horizontle plane but I would certainly think they could start milling from the other end & stop at the last port flange bolt hole.