[strictlypersonl]

The '62 (260/289) used 3" tubing on roughly 16" centers. The 427 used 4" tubes on a slightly wider spacing. (I'm guessing on the spacing numbers...)

I couldn't find them on Cobra Restorers site, but they used to have drawings of the 427 chassis (not perfect, though), and they might have drawings of the small block chassis.