Do all A bodies have overheating problems?

check your belts, that thay not setting way down in the pully riding the bottom side slipping threw the pullys! seen it happen when wrong spec belts used or pullys wore out, it rare but happens! might try a different thermostat, i like the ones that stay open when thay fail. my 71 340 duster with stock radiator high compression over cammed over carb'ed threw stock manifolds with no shrowd and a flex fan never got above 185/190 stop n go 100 degree days...over 10 years never a issue,dont even think it had a thermostat, never even looked....DWB