I have a VMax 46 engine mounted inverted on a Venus 40. Had this engine on a PT-40 trainer and on the test stand and ran just fine. It's being very fickle now that it is inverted (have to actually start it on a stand with the plane upside down). Any pointers on running inverted engines? I've got a Saito 91 that I am going to be mounting inverted as well on a P-51 so any help on this one would be appreciated as well.

Thanks.