Help on single driver Lowther Acoustic 115 speaker

I have a set of Lowther Acoustic 115 cabinets that I was told had AER MKll drivers in them but what I am seeing is measuring the depth and opening they would be to deep to go in them. I am thinking these were made for 6" drivers and then someone opened them up to try and put 8" drivers in and found out they really won't fit. So the opening is 7 1/2" and the depth to the back is 2 3/4" or 7cm. And the wires where run so anything with a large magnet would hit the so really only have 2 1/2" of actual clearance unless the magnet is not to big. I used spacers for some Audio Nirvana's with okay results but thinking there is a much better solution. Visually not what I was hoping for. So is there any good 8" fullrange drivers out there with a front mounting depth of less than 7cm or 2 3/4". Just for reference the spacers for the Audio Nirvana's are 1 5/16". Thank you for any help you can provide.