Hi All,

This is what I am doing now with my McCoy 40.  It has had the piston/jug heat treated to help it last longer while using a muffler.

PA NVA

10-6 Rev Up EW prop

Thunderbolt plug

Sig 10%-25% all castor with 4 oz. castor added.

Adapter to bolt ST 46 mufflers to the hole in the exhaust port center.

Great 4-2 and easy to set.  It pulls the Parrott P-47 real easy!