How close is to close?

I am going to retract my suggestion of the M-B fan. Since I had to use the spacer collar to fit the Mopar clutch on the M-B water pump, that means the hole in the M-B clutch must be too small for the Mopar water pump (duh!). You couldn't use their clutch without drilling the register hole bigger (pain) and might not be enough meat left on the shaft after that, so probably a no go. It is a much thinner clutch though. I just removed one yesterday to change the water pump and had to grind a wrench to get on the bolts. Looked at my 383 and its clutch has a long shaft with room even for a socket wrench on the bolts.