360 Magnum to A833 trans
The American Powertrain flywheel is the way to go. They have a version that is compatible with the crank sensor in case you want to run the factory EFI, too- you just have to call to order it.
Your clutch and pressure plate will fit just fine.
And I agree with JYH- don't cut the input. People do it, but people do a lot of things I wouldn't recommend.
I've seen people put in a pilot bearing. Or cut off part of the output shaft. I'm assuming the bearing is the way to go.
OMG, this is NOT an either/or proposition- you MUST run a bearing or bushing no matter whether you cut the input or not!
The deciding factor is whether the crank flange is fully machined for the pilot bushing/bearing or not.
The rebuilder should be able to tell you. If he can't, run away.
If it is fully machined, then you can run either the bushing or bearing. If it is not, then you're left with running the bearing, which fits in the convertor pocket. BUT you still need to confirm that the recess is deep enough for the trans. input shaft. If it needs to be deeper, you can drill it out by hand since you'll be using the convertor pocket in the crank flange to register the bearing.