I owned both bikes back in the sixties I had a Bonneville and a BSA GOLD STAR TWIN that was a 650 lightning engine in the GOLD STAR frame and beleive me the BSA was faster stock and I proved that by beating all the TRIUMPHS at the drags and the BSA also handled better as it used the Gold star racing frame and racing brakes and the BSA gearbox was better Of course I then bought a 1955 VINCENT BLACK SHADOW that had lightning cams ,pistons,big valves , triple valve springs bigger carbs and 2inch straight through lightning racing pipes and that thing left them all for dead . I also owned a 1961 HD XLCH sporster that had factory racing cams and 36 inch racing pipes and a bored linkert carb I held the national record with that bike 12.4 1/4 mile @ 106 MPH BUT the VINCENT was faster and quicker 11.7 and 118 MPH way faster than the other bikes and it would run 150 MPH top speed