a 275 with +40 offset is starting to rub already (no stupid negative camber) in essence you want to add another 20mm of tire + another 28mm of offset for a total of 48mm (almost 2" further out) I think a 305 may work if you went the other direction on the offset maybe a +52 with a 305 and you cut cut the wheel lip and used a coil over. In theory you can use some over fenders and bolt them and cut the metal to get yourself some more room.
you can always try and see how it looks it just take some time :-)