I have a diagram in one of my manuals at home that shows the
oil flow path for, I think, both a 428 and 427. I'll check it this evening when I get home and let you know what it indicates as to flow path.
Plan at this point for my build is to plumb the accusump into a T on top of the
oil filter adapter where the
oil pressure sending unit now attaches. May have to rethink (re: backflow) as I look into it more deeply.
DonC