An extra race, the return of two-strokes and an additional TT course have been announced for the 2008 meeting.
Another Supersport class race has been added to the programme around the Mountain Course.
Two-stroke racing will be held the day after the Senior TT around the Billown Circuit.
The Lightweight and Ultra Lightweight races in the south of the Island on Saturday 7th June will carry full TT status with a prize fund reflecting this.
The races at Billown will feature the first TT mass starts since 1959.
Other courses used for the TT were St. John's and the Clypse.