The key is to make them fit as much stuff as you can. I have spent a TON of time fitting/modifying my small block kits to work on as many configurations as I can.

A body, b body, e body, with power steering, without, manual trans, 904/727, driver side and passenger side lower radiator houses, factory battery position, mini starter and old style, etc...

I think you'll have a hard time getting interest or the volume you need unless you can dedicate to taking the time to make the design work with a lot of combos. Limiting to Shumaker mounts and only a body could be a tough sell.