RE: Venturi for 061 Wasp
They are certainly "ABC technology" but I think it is actually AAN. The cylinder has a hard surface all over and below that it doesn't look like brass to me. The piston is aluminium looking, hopefully with some silicon in it.
They shouldn't need much running in at all. I ran 2oz of 80/20 fuel (full castor and no nitro). Then I've flown it on 702010 all castor for about two years. The piston/cylinder is not too bad, it is the quality of the rest that is a little poor.
If your engine is running too warm I really can't see where it comes from other than a too large prop or wrong compression setting. The crank to case fit is so sloppy that there shouldn't be any extra heat from there. The cox 6x3 are a little too high load, the graupner 6x3 are just about right and the APC 5.7x3 is a better match.
You could add another (and proper) head gasket perhaps and see if that helps. It really should hold a needle setting more or less right from the start.
Another thought, have you checked the internals? The quality on these engines is really poor and you might have something that is not properly fitted, like the conrod for instance.
There is plenty of information on these engines on this forum, just do a search.
They are only a poor copy of the Norvels though and that it is way you don't see much discussion about them here anymore, I guess.