Hey all I did the Scarebird conversion on my 1964 Chrysler a few years back but I've never been able to get a dual diaphragm booster in there for the pedal feel that I want. I've ordered 2 or 3 but nothing fits right. My early car (and all pre 65, I assume) has a skinnier and more rectangular bolt pattern for the firewall and most of the late boosters don't fit. I think there should be a later Imperial that works, maybe a Bendix unit. Can anyone help me with the right part number to order for the car or am I too deep into the weeds over here?