Bene Rodrigues won this weekend the Brazilian NATS using a OS 72FSa. I supply him this engine just a few weeks ago. He told me he just added an extra gasket and basic restrictor. His engine ran perfectly all the time.
FWIW, the engines used by the top 10 were:
1- OS 72FS
2- Retro Discovery
3- PA-75
4- PA 65
5- PA 65
6- Enya 61CX
7- Retro
8- ST G51
9 OS 56FSa
10 ST 60
Martin