In order to design the engine mount for my Corvair engine,  I had to mock it up in place.  To do this I made a 3/4" plywood copy of my existing firewall,  and mounted it to a rolling engine stand.  I attached 2x4's for the engine to rest on,   hopefully out of the way of the position of the tubing making up the mount.   The engine is now sitting at the right height in relation to the thrust line,   and it can be shifted fore and aft as required for the appropriate rear clearances.   I may end up recessing the harmonic balancer and the rear mounted starter ring gear (not installed at this time) into the firewall.

This is my 110hp RW engine which will be built for my Dragonfly.   The 102hp YN engine that will be going in the Q-2 is being built,  so I assembled this engine for mock-up purposes.  To save weight,  I left the pistons, rods and cylinders out of this engine,  and it their place,  I cut electrical conduit to act as spacers so the heads would be located properly.  From the weight savings,  I can pick up this engine by my self if I need to,  but I usually get some help.

The idea here is to position the engine so the engine mount can be fabricated.  Once it's complete,  I'll remove the 2x4's and suspend the engine by the mount.  At that point I'll work on intake and exhaust.  Right now the exhaust stacks are resting on a 2x4,  making the exhaust system impossible to fit.