Healthy gas temp ?

which would be a healthy exhaust gas temperature for an engine 4g63 evo9, 10.8 CR, precision 6266, 40 psi, and outside temp around 100 ° F, gas Q16

where are you measuring it?

Your EGT will depend on a number of factors including the location of the sensor, the type of sensor (exposed vs encased tip) and the ignition timing. For these reasons it's impossible to give you a 100% accurate EGT that we can define as safe. Personally on the EVO 9 drag car that we set the world record with (Q16, GT4202 turbo, 40-45 psi boost) we would see EGT reach around 900-950 C in the deep end. If you go much above 1000 deg C you risk damaging some turbochargers as the turbine material may not survive.