I just started up my new SBC this year. I started at 32 @WOT and it was flat above 4000 rpm. I'm up to 36 now and it showed substantial improvement. Going to try more when the weather breaks - only 1k miles on it so far and was focused on carb tuning first. You should add vac advance for street driving. It has no effect during WOT. Improved throttle response, better mileage, cooler running, etc. Run with MANIFOLD vac - not ported vac. Idle timing advance should be in the 20's. Cruising/low/no load 2500 rpm should be around 50 advanced!