I have a 4 spd. Saginaw from a 77 Monza with extra casting on the bottom of the tailshaft. I'm putting it in a 79 Nova. The problem is this extra casting gets in the way of the shifter mounting plate that needs to mount up flush with the bottom of the housing. Can I trim part of this housing off? The picture below shows a line I roughly scribed (looks dark) of the small piece that would need to come off the bottom of the housing to make it flat. It looks like it is just extra solid cast iron that could come off.