Trail fit magnum to 76 auto body 
 
Trans in  position 
I had to cut the tunnel to get the box up to the correct center line
the section removed  is the area  where the original auto shifter  was mounted .
this section  protrudes down towards the gear box about 32mm.
the hole will serve as the shifter position. 

 in the photo above  you can see the trans mount  the bottom of the mount is 10mm below  a lone taken across the bottom of the chassis.

this photo show  gear box  sitting at center line of original box  
there is just adequate clearance.
note the top of the shifter area is at an angle  that is standard  in the design of the gear box its about 17 degs to the left side. 

this is a 76 auto body  I would think there will be less room in a 70 model manual body I will know in a few months if that is true.
the photos  could be better but that is how it is  when you take them with a phone in the middle of the night 
Bfit