Motor Wheel Co. Magnum 500 ID Question

[SHELB66]

Most of us know that the Motor Wheel Co manufactured the chrome Magnum 500 wheels for the '66 Hertz Shelby.  The wheels are usually marked with 795c or 795 which is one of the indicators for a correct wheel.  Mopars use a similar wheel with that marking but with a different backspacing.  There's a current eBay auction for some Olds wheels with a 833c marking.  I obtained some 14x6 chrome Magnum 500 wheels many years ago with a different profile and a 842c marking.  Does anyone know the application for wheels with this number?  Thanks!

Craig R.

[SHELB66]

Here are some pictures.

Craig R.