I would bet if you turn the adjuster in, pressure will drop. I think it takes spring pressure to hold off the fuel pressure. 3 to 4 will be plenty, the carb will lean out slightly with less pressure, so a float adjustment might be needed if it runs right as it is. If it smells rich, then less pressure will cure the smell and make it run better.
You might have a high pressure mechanical pump installed, Carter made them and still does. It will have screws around the middle, where stock pumps are crimped together. The Carters can be taken apart and the base rotated.
If it runs right, doesn't flood over, smell decent at the tail pipe, then don't worry about it.
Joe
