Cutting floor to do a four speed conversion

[Ghoste]

I have a chunk of b body floor from a 69 road runner four speed car that I've saved because its a great template for cutting to do a conversion.  Here is my question though.  The factory obviously must have cut the floor before the crossmembers were in and I've read posts from people doing a cut for a four speed with the important warning about not slicing into the torsion bar cross member.  So why is the hole so big in the first place?  Obviously the trans and shifter aren't going into that space.  Why not just cut the hole up to the crossmember and cal it a day?

[metallicareload99]

Was the factory 4-speed hump butt welded in or was it done different? If not it makes sense to make the hole larger than necessary if the hump was just going to be lapped over it 

[Ghoste]

It was spot welded over top from the inside.  I have found out since that the hole was stamped out before the pan was placed in a die for forming and that they are sometimes not in the exact same spot depending on how the floor formed and so it is possible for it to go slightly over the area where the crossmember would be.