Several folks who have that old Holley 1904 wind up with flooding problems due to rebuild kits with oversize fuel inlet needle orifice. Some of the guys end up fixing the problem with the addition of a fuel pressure regulator, but you must use a bypass type, which means you gotta modify your gas tank to accept the return line. Several brands of the non-bypass type regs wont handle the pressure and end up blowing in short order.
Reducing pressure can be done by remounting fuel pump on a shim, but that is very cumbersome to figure out the right depth of shimmage.
More info: look into fordsix.com and then pick the Vintage inline sixes category in the forums. There are lots of guys in there who mess around with old 215 and 223 Ford I-Blocks with the Holley 1904.