Hello, I'm wondering how similar these two transmission tailhousings are. I understand the c6 is an inch longer, but are they dimensionally the same besides that? The reason I ask is I have bought a gear vendors unit with a c6 adapter but I need a c4. I'd like to get a used c4 one but haven't had much luck in finding one. Would I possibly be able to use the c6 adapter if I shave an inch off is why I'm asking... The exchanged price at gear vendors is $650, so thats a lot of money for an inch.