Had Dan at the Mustang Barn convert my vacuum single point dizzy to a mechanical dual point a few weeks ago. I replaced my OEM 240K mile 289 A-Code in my '66 GT with a K'ish 289 build this summer and the Dizzy just couldn't keep up. It kept falling on its face above 4500RPM. So I talked to Dan and he had the solution. Not really a good video, shifting right at 6000RPM...still pulling. Enjoy!