Slant six Holley 2280 stalls when stopping

....pushed the wrong button, wasn't finished! High idle speed promotes dieseling, so that could be the cause of the dieseling.
If idle vacuum is lower because of the new cam, it might be causing the PCV to oscillate. This causes rough/unstable idle & stalling. Try disconnecting the PCV & plugging the hose.
If the cam has increased duration, depending on how much, it is going to want more initial timing. This is very easy to check: with engine idling, loosen dist clamp & slowly turn dist CCW. If rpm increases & idle smooths out, it wants more timing.