Bell, a factory McLaren GT driver, produced an impressive run on the 1.86km Goodwood hillclimb in his McLaren 720S GT3X to clock a 45.01s effort despite the threat of rain.
Popular American extreme motorsport competitor, Pastrana, had topped qualifying in a modified Subaru WRX STI and was up on the first sector, but was unable to match Bell after a wild slide towards the end of the run.
In the end, Pastrana was left to settle for second 1.19s shy of Bell.
The outright hillclimb official record still belongs to ex-Formula 1 driver Nick Heifdfeld when the German clocked a 41.6s time in a McLaren MP4/13 F1 car back in 1999.
A 1988 Spice-Cosworth sportscar driven by Jeremy Smith secured the third fastest time having sat at the top of the times before Bell and Pastrana took to the course.
The shootout was punctuated by a lengthy red flag period when Jack Tetley lost control of his 2012 specification Chevrolet Camaro NASCAR on the run to the finish.
Tetley put a wheel on the grass which sent Chevrolet spinning a high speed into the hay bales, causing damage to the front and rear of the car.
One of the hotly tipped favourites, six-time Goodwood shootout winner Justin Law was a notable absentee from the final despite setting the fourth fastest time in qualifying.
However, a spin at the Flint Wall in a morning run inflicted significant damage to the 1993 Bud Light backed Jaguar XJR-12D that was driven in period by David Brabham, John Andretti, John Nielsen and Davy Jones.
Five-time Le Mans 24 Hours winner Emanuele Pirro set the first real indicative time with a 58.63s in the stunning Ferrari 250 GTO ‘Breadvan’.
That time was eclipsed on the next run as Kenny Acheson fired in a rapid 52.27s in the Group C Sauber Mercedes C9.
Ferrari 250 GT SWB ‘Breadvan’ H
Photo by: Carl Bingham / Motorsport Images
Ric Wood was next to impress in an ex-Rick Kelly Holden Commodore V8 Supercar, jumping to second fastest just 0.86s adrift. The time put Wood to the top of the touring car category ahead of Julian Thomas’ Andy Rouse liveried Ford Sierra RS500 and a 1999 BTCC super touring Renault Laguna driven by Mark Jones.
Action resumed after the red flag stoppage with spots of rain in the air but it failed to halt factory Toyota BTCC driver Rory Butcher who put the Sppedworks Corolla third briefly, before his Motorbase/MB Motorsport BTCC rival Jake Hill took to hill in Ric Wood owned HKS liveried 1990 Nissan Skyline GTR.
After Bell, Pastrana and Smith’s heroics, Hill would end the shootout fifth overall and top of the touring car class while last year’s Porsche Carerra Cup Great Brian champion Harry King took fourth.
The Praga R1 driven by Ales Jirasek was sixth ahead of Anthony Reid, who piloted a former Carlos Sainz Ford Escort WRC, while Acheson was eighth.
The top 10 was completed by Wood in the Holden Commodore followed by Butcher.