uinless you go with a fox body booster, it is almost not worth the added assist the old boosters gave, since theye were single chamber units. if your car has a manual trans, you can not fit the booster in place anyway due to the cltch pedal rod.
too much A/F wil not cause it to overheat, it may cause it to over flow due to th pressure relief on the cap.
if it is overheating & would suggest frst changing the thermostat. if it is shutting down, does the car have points or electronic ignition/conversion? many times the problem is in that area, getting hot & shuts down
let us know if you need more assistance, fill in your biuo so we know more about you, were yo uare from etc.. & good luck,

 

Sounds like you may have a sticky thermostat. Its a very easy fix.

If you want to add water to your mix, there is a little drain on the bottom of the radiator.