What weight oil are you running

On my 367 combo;
with an HV pump,a large pick-up, and no 90* adapter,
and having done the oiling system mods per the sticky, except no valley cross-over tube;...15w40 blows oil out at the filter pad at higher rpms. (I have been known to shift at 7000/7200)
Even after; I doubled up the plates and doubled up the holes, and increased the hole sizes, and bored out the filter attaching adapter, and "ported" that circuit as far as I could, from pump to cam, and drilled out the oil-supply to the rocker shafts, and slightly increased the side clearances to the rocker arms.
After I switched to 10W30, all; was good.