I had to do the same thing with my OS-RG. THe carb boot on that thing is huge. It rubbed the upper center diff plate and the rear brake actuating rod. It would hit so much that it would actually fold over and pinch.
The Nova motors have a much smaller boot so they fit fine.
There are a lot of guys around me running the new VG. I'll check and see if this motor had the same problems.
I set mine up so I could still use the stock servo horns. This design is great and definitly something I wanted to stick with.
Car is running great.
TEX