If the distributor rotates CCW at idle the vacuum line is connected incorrectly. There should be NO distributor movement at idle. As the RPM increases, the distributor housing should rotate CCW (opposite the rotor motion) and stay there as long as a steady speed is maintained. If the throttle is opened quickly, the housing will rotate CW and stay there until the speed increases and stabilizes- - - -then it will move CCW and stay there again. If your timing is being set to the "ball and pointer" with the vacuum advance operating, you're about 10 degrees late on the initial timing. That will cause terribly poor performance. Disconnect and plug the vacuum line at the distributor- - - -THEN align the ball and pointer at idle speed.

Yes, the heat riser flap valve needs to function properly- - - -no, it will not cause the problems you're having.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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