Yes they are compatible. The series 3 adapter will sit right in the 364c with no issues. One thing to note, the series 3 adapter is not long enough to engage the push button retaining pin mechanism that normally prevents the head from falling out when the tension adjustment is loosened all the way. It's not a problem, just keep the tension snug and it's a non issue. You can run the tension out to around 45* and get a makeshift pan feature without the tripod releasing the series 3 adapter. Or just leave it tight.