What Bell Housing for BB Duster?

I wouldn't say direct swap. Yes, it bolts into the same location as a bellhousing and you shouldn't have to do any cutting of the floor, other than installing a 4-speed hump. You will have to create or buy a bellcrank assembly, which includes mount bracket for scattershield, that is a bit differently than stock big block. However, if you go hydraulic clutch, that will take that out of the equation.

Some scattershields limit you to one size clutch and others will let you run either.