With the 2007 1:8 IFMAR World Championship just behind us, and with Collari's stunning 8th title win we dug in our archives and we found that Lamberto Collari won the WC title with NOVAROSSI engines 6 times.
Here is the list we have in our archive:

1987 - Re-Pete Fusco (USA)
1989 - Lamberto Collari (Italia)
1991 - Lamberto Collari (Italia)
1993 - Lamberto Collari (Italia)
1995 - Lamberto Collari (Italia)
1997 - Lamberto Collari (Italia)
1999 - Adrien Bertin (France)
2001 - Kenji Osaka (Japan)
2007 - Lamberto Collari (Italia)

(The world championships are held every 2 years)