Matt,

Looking at those numbers it appears the Syssa with soft mount is not going to fit in the nose of the Aries. The distance is 6-3/16" from the firewall to the prop hub exit in the cowl, and it appears that even the OS 1.40RX was a pretty tight fit.

Also the pipe tunnel is enclosed - the pipe slides in from the front of the fuse, behind the chin cowl - and it too would be a very tight fit, if it fit at all.

Well, my friend also has a Petrel that was designed for petrol, so maybe we will give that one a look.

Into which model are you now installing the Syssa (after removing the ZDZ)? I am starting to wonder if any ARF designed for glow is going to work without doing major surgery to move the firewall back.