When converting a GMC to full flow you can keep the side fittings down to 1 for clearance if you put the oil back in at the front of the gallery at the front of the block. Bob Corbett does this; you can see it Aug 06 12Port news. Using an external oil pump and the front filling eliminates any side fittings..Good Luck. Nice TP filter..C-Dan. I use one to clean my parts washer fluid

216.158 MPH 12-Port 302 GMC on 70% 171.0 MPH 302 stock head on gasoline 7 years later