Rocker oiling or lack of .

Any chance you left out the inner rear oil gallery plugs? I recently forgot the left side inner rear plug and left side had low volume. Look down inside the distributor hole while priming. If you see a lot of oil splashing around in there, this could be it. If not, I would start wondering about the oil system mods, as long as you still have concerns after doing the degrees 70aarcuda mentioned. Maybe something did not go as planned. I don’t remember if you already had this combination working previously.
Oil pump priming issue