Six cylinder convertibles are heavier than an eight cylinder coupe. Yet they still get the smaller 9" diameter brakes the six cylinder coupes get. Supposedly, Ford tried to mitigate this deficiency by installing the 2.25": wide rear drum brakes from the Falcon station wagon on the Mustang 6 cyl convertibles. But it never happened to my car. It had the standard1.5" wide rear drum brakes since new. Some quite knowledgeable Mustang masters have said in this forum that they doubt it ever happened, they have never seen the wider convertible back brakes factory installed. So here's the survey question - Are there any 65-66 six cylinder convertible owners who have, original from the factory, the 2.25" wide drums on the back of their car?