Mine tapped back in at the existing 1/8NPT stock location...just slightly to the rear and below the accelerator bellcrank mount point near where the return line feeds the main oil gallery.
The front 1/8NPT port, where the original bypass filter line entered is now plugged. I was a bit concerned about line bleed-back but have instant pressure once I hit the starter.
Just noticed on your pictures that you are running a bypass filter....not a full pressure filter system. On my original bypass system, I
used a "T" fitting with the bypass filter line and oil pressure line hooked up at the block. The bypass filter only filters a limited amount of oil and I discovered, bleeds off about 5-7 psi from the engine. When I added my dual carbs, I blocked off the front 1/8NPT port and the 1/8NPT port in the "T" fitting and noted the increase in oil pressure. I don't know if having your gauge up at the filter would give you the most accurate reading. I don't think this mount location would have any effect on the actual oil pressure, just might effect your gauge reading. You might toss this out for someone who has more experience with this engine.
Dave
