Early A-body steering modification
question: how fast ratio are you looking to go? i mean, factory 16:1 is already darn quick on the street...
boxing the idler and making it double shear is a good idea. i did that on my 64 & 65. however those were kinda, sorta track cars. i don't know what your final destination is, but unless you're running a pretty aggressive front suspension set up with sizeable tires, just upgrading to a rollerized idler might be enough.
don't get me wrong, i'm all for the double shear mount tho.
the c-barge center may not work in that the width might be a problem (possibly overcome with a custom shorty situation) but more importantly it looks as though it has zero drop which means it may come into contact with the oil pan. or maybe not, it might be far enough back. which, could potentially present a whole other set of issues in the exhaust clearance department.
interesting and ambitious project though!