It began life in the rear of a German vehicle and is feeling and looking right at home getting transported in one again.
In order to get the CG close to spot on I am going to mount the wings and empennage on the fuselage, fill both tanks with water and then sit in it. A temporary bed mount will be hung from the firewall and the engine can be slid forward and aft until the LE is at the suggested rear CG of 1/3 wing chord at maximum weight.
The permanent mount dimensions can then be determined based on this figure.
Out of interest I did a search on the engine block number. This one was born in 1966 the same year as me. It was originally 1300cc and had an output of 50hp.