I haven't checked into it yet, but I wonder if a set of mounts/biscuits from a '55-'57 Chevy station wagon would do it? They're readily available, and I can see Chevrolet carrying something like over from other models/years. Shoot, they used '56-spec 322 Buick Nailhead engines in their bigger trucks through '59, and our Deluxe steering wheels were Bel Air wheels, weren't they? And after buying a '60-'61 V8 van shroud, I'm very certain they're the same as '58-up passenger car shrouds.
-Brad