Double check your dwell and timing (and plug gap), that is usually the first culprit in having warm starting problems. Often point gap isn't enough because the relationship between it and dwell changes as the distributor wears.
Another likely culprit is that your valves are set too tight, and the lash goes away when the engine is warm, hurting compression at low speed.
Also check the idle mixture and the carb for leakage. Air horn gasket leakage to the inside can cause rich idle and intermittant mixture problems that make warm starting tough.
Also, check for vacuum leaks. Usually hard warm starting is an ignition problem on 235's, though.
