it is installed on the mustang. The one installed on the trainer works perfectly! (it even survived a crash)

And regarding the cowl, there is a hole on the side, and adjustments are made easily.

As a prop I am using an 11x6 and the fuel is the same as the one i use for the trainer.

Right now I blocked that hole, which on the other engine do not exist (maybe only a small batch of engines had this hole) because when I blow from the silencer a huge amount of air is going out from that hole.