I have a 54 Mercury with the 256 engine and have used adapters and a 1 inch spacer to install a newer style Holly 4 barrel carb, and I was wondering if the 1957 distributor would work in this block so I can have both centrifugal and vacuum advance. I know about the oil pump and hex drive change needed as well as the drive gear swap. I bought a 61 292 distributor but the housing dimensions are larger than the block  opening. Has anyone else used the 57 distributor in this block or will I have to remachine the 61 housing to fit.
Thanks in advance, Bill