That appears to be a late 60s Fairlane or Falcon toploader but I'm not sure of its tail housing length - probably the mid-length with an overall length of 25.5 inches. But from the pictures on this site for that model, it looks like the shifter mounts are mid-point on the tail housing.
Toploader id
I suspect you will need a mount that moves the shifter to the rear end of the tail housing to fairly accurately reflect the original 427 mount. But, I'm not sure as it can depend on how far back the engine is mounted, etc. You are probably safest to wait until the drivetrain is in the car, but you could mock up the drivetrain and determine where the shifter mounts are in relation to the engine mounts (or transmission mount and get a pretty good idea as to where it will fall on the tunnel.