The pictured engine was the "Perrier-Cadillac" engine as fitted to the AC-3 Sentinel. AC-1 had the left and right engines as pictured, but the top engine hung out over the back, making for a long and awkward shaped engine.:
The AC-1 engine installation is the picture "Twin Caddy". The third Cad V8 is out of view in the upper part of the pic. See
http://www.mheaust.com.au/Aust/Resea...sentinelmk.htm for more info.
Contrary to most published litrature, there is at least one other AC-3 surviving besides the one at AWM, that owned by John Belfield. John's AC-3 was built up from produced-but-not-assembled components and is actually more complete and less worn than the AWM's one which underwent the trials. Perhaps Keith could get out to visit John for some current pics of his AC-1 and AC-3. International MLU'ers will know John Belfield and his Melbourne Tank Museum from the Year of the Blitz video, and if you don't have a copy, well you know what to do!:cool