Need advice on oil for two scoobys, classic sti ver6 and an 03 jdm, both pushin circa 370bhp, both having the same problem... Oil temp very high and oil pressure very low.

Not pushing the car particularly hard...
Temp 100-120
Pressure dropping 1.5-1.0

Both using Titan 15w 50.

Would a thicker different temp rated oil help in keepin the pressure up and keep the temp down?