Fan Clutch

So I have a 68 Dart with the 225 slant six. I have an aftermarket aluminum radiator in it. I would like to put in a clutch fan. I am currently running a 6 blade flex fan, which cools it fine, but it is loud and is probably taking up to much power (this is a convertible so it needs all the power it can get).

The problem is that the radiator is 2 rows, it is a lot "thicker" compared to the OEM replacement one row. And the standard fan clutch pushes the fan into the radiator (not good).

So I was wondering if anyone had this problem? I do not want to change the radiator out due to it working extremely well.

Would anyone have a part number to go on for a shorter shaft fan clutch?