Re: Curious about the engine, :question:
I did the same thing on my Dax engine before installing, drilled and tapped it to 1.4 x 20 and bolted it directly to a bracket welded to the frame. I don't like torquing bolts directly into the aluminum so I used longer bolts with a jam nut so the bolts go in just above finger tight then the jam nuts get torqued to 10 ft/lb which prevents thread wear in the aluminum.
There was enough room to drill and tap for the M8x1.25 hardware but since I already had the 1/4x20 on hand I went with that.
The case also had the narrow frame spacing on the front side but there was also plenty enough metal for me to use a die grinder and a 1" carbide rotary file to widen it and match the angle to my frame.