DWD
I have heard of it being done. Try Paul Mitrega at inverell. He has converted a fair few 182's to 180's.
The 182D shares the "same" airframe with the 180G.
The 182D has the swept tail though.
On another matter, I have just put the IO-550D 300hp in my 185.
This replaces the IO-520D 300hp for t/o and 285hp continuous.
Goes damned well. 145-150 ktias at 4000 25"/2300rpm.
Trues out to around 150-155 KTAS for 68-72LPH.
Take off roll is reduced slightly and the climb rate is improved.
It's going to be hard to keep slow for any survey work.
185.