Michael Dunlop set the fastest time overall on Tuesday night during the first timed qualifying session for the inaugural Classic TT races.
Dunlop cracked the 120mph barrier in the Formula 1 class on his 1982 Team Classic Suzuki XR69 with a speed of 120.894mph on his second lap.
The Northern Ireland rider was victorious on the machine in the Classic Superbike race at the Manx Grand Prix in 2012.
Dunlop will also ride a Molnar Manx Norton in the 500cc race on Saturday.
Jamie Coward was second fastest in the Formula 1 category at 116.545mph on a Kawasaki ZXR 750 followed by Steve Mercer (Yamaha FZR 750R) at 115.856mph and Paul Owen on a Kawasaki ZXR 750 at 113.705mph.
In the Classic TT 500cc class it was Olie Linsdell who topped the times at 111.385mph on a Paton, with 20-time Isle of Man TT winner John McGuinness second quickest on Roger Winfield’s machine, previously ridden to Manx Grand Prix victory by Ryan Farquhar, with a speed of 111.193mph.
Bruce Anstey was next on a Manx Norton at 106.066mph followed by Seeley–mounted Cameron Donald (105.949mph), Jamie Coward (Manx Norton) at 104.912mph and Ian Lougher, riding a Royal Enfield, who lapped at 104.7mph.
William Dunlop was eighth fastest on the Davies Motorsport Honda 500-4.
Lincolnshire’s Gary Johnson was tenth on the iconic MV Agusta with a speed of 102.917mph.
Chris Palmer led the way in the 350cc class on his Drixton Honda at 100.495mph followed by Dan Cooper (Molnar Manx Norton) at 97.831mph and Jamie Hamilton on a Honda, lapping at 97.584mph.
The inaugural Classic TT races get underway on Saturday with the 500cc race, with the 250cc/350cc event and the combined Formula 1, Formula 2 and Formula Classic race taking place on Monday.
The traditional Manx Grand Prix, celebrating its 90th anniversary this year, takes place next week.
Dennis Booth clocked the fastest time last night in the Senior MGP class on his 750cc Suzuki at 113.19mph.
Andy Farrell (Suzuki) was next at 112.589mph with Gavin Lupton third fastest at 110.572mph, also riding a 750cc Suzuki.
Michael Sweeney topped the times in the Junior MGP session on his Yamaha R6.
The Skerries manlapping at 116.29mph with Stephen Harper in second (114.279mph).
James Cowton (113.797mph) and Stephen McKnight (113.616mph) were the first four.
Sweeney also headed the Supertwin times on his Kawasaki ER6 (110.238mph) with former Isle of Man TT Formula 1 winner Nick Jefferies, who is also competing in the Classic TT on a Honda RC30, second fastest at 107.278mph.