As title states, i have been thinking about this some time now. Could you machine 13B rotor housings to 12A width and use cosmo end plates? There is a lot of housings out there with chrome flaking on the edges, not useable for a 13B.. I know that housings can be narrowed down to 12A spec, but apart from the obvious, as the need for a custom intake and pan, is it possible?

It would certainly be a custom job, but wouldnt it be cool to have the lightweight 12AT rotors, in the huge port cosmo block? Also, the shorter shaft would mean less flex..

Can anyone think of major issues that would have to be adressed?

 

No it has already been done.

I have done a s5 engine with machined down housings for a customer.

They work excellent.

A person ive know for a long while has almost completed one cosmo 12a.

He is on Ausrotary and his nick name is ANG_RE i think.