19 cc domes would not be alky comp, I have 180 psi and I run Vp 110, if u run 19cc and your comp is 150 I would run race gas.I know some people that set there bikes "10 dm" up for low comp 130 to 140 and run them on alky. Alot can change you comp, like port timings Etc alititude also plays a big part. My bike here in cali at sea level is 180, when I go to Utah it will drop to around 140.