1 have a 1969 roadrunner with  383 4 spd with 22in rad no shroud she runs  at 220 degress unless I put heater on then she will run at 190 tried replacing water pump put new 16lb cap flushed system cleaned rad no luck also run car with out cap with heater on looking for air pockets still runs hot any suggestions would be appreciated tks tony  

You really do need to have that shroud on it does help. I live in Fl and the only way to keep my 340 cool is to run it without the thermostat, my buddy has a 440 and that's what we do to keep them cool on those hot days. But we also don't have to worry about a heater during the cooler months. Even when I lived up north I pulled it out, actually I don't think its been in for the last 20 years. Good luck  

By turning on the heater you are adding extra core size to your rad, so whats the problem, probably need to replace the rad.
A big block should have no less than a three core rad, however the new aluminum rads which are cross flow also do a nice job. Put the largest rad you can in the car and be sure to install a new thermostat since it is likely damaged from running it at 220 degrees.  

tks guys i will try that and let u know