Not gonna happen.
Correctamundo - and that's all it will ever work in. These things are far too system specific to just swap over - and the '020 and '030 busses are very not alike. At best you might get it to work in a different '020 machine: even then you will likely run into problems with component clearances.
Best use for this would be into a Mac II * so you can have a fast-ish five six * slot Nubus machine, that IIRC will run System 6 *. It should compete pretty well against a IIfx, and best of all you don't have to chase up that weird IIfx RAM *.
* Supported Mac OS: 2.0-7.5.1, 7.5.3-7.5.5
128MB max RAM with MODE32 (8 x 16MB 30 pin SIMMs)
http://www.everymac.com/systems/apple/mac_ii/specs/mac_ii.html