Which engine oil to use for road/track day ?

I was recommended by my engine builder to use Memorex 0/40.

What are you using gent s as I will change engine oil soon: ie;

-Is 0/40 OK ? (always used it and is good but need refill once in a while
- Which trade mark ?

Engine. SB302.
IDA 48 Weber.
Edelbrock heads
Est 380 HP

As long as it has atleast 1000PPM percentage (I prefer atleast 1600ppm) zinc or ZDDP in the oil its fine.
I must admit, I prefer 15W40 or 15W50 mineral blend.
Had better oil pressures on a hot day racing ( Capri V8 & Capri 3.0) with 15W40 mineral compared to 10W40 semi syntetic (both Valvoline brand).
I have an decent size oilcooler with stat and oiltemp gauge and steady temps around 110' Celsius.

Semi & syntetic can handle more temperatures, but with a decent sized oilcooler you can handle any oil to its grade.

Btw, i am running this Belgium stuff in all... SAE 15-W50 - 5 Liter - Oldtimerolie.be , (1000ppm) but i do ad some Cam-Shield ZDDP to raise the levels to 1600PPM.

With a roller cam & roller rockers you can get away with less ZDDP.

My new build engines are always run-in on 20W50 Valvoline VR1 Racing oil as it containes 1600ppm ZDDP.
I'd look at oil pressure while on track to determine which viscosity. My engine had cold idle of 90 psi, I dropped from 10W40 to 5W40, cold idle now about 80 psi, hot idle about 65-70. Builder recommends 15W50 for racing. That's with a LS motor.