The crucial thing isn't what's homologated for the Manta axle across all platforms but what's homologated for the Chevette. The homologation papers only list the drum brakes, one rear disc setup, part 54-188, and an optional rear caliper. I think both these are the the AP Racing calipers.

There are plenty of non-homologated conversions available, and how bothered anyone would be if you used an non-homologated setup I don't know, but you'd always be open to having it challenged.

Gordon, I seem to remember that conversion being available from Peter Maiden, but I can't remember any more about it either!