Aight. Just for kicks, let's try something. With it idling in park, first idle it down to about 850 in park. Now with the vacuum gauge hooked up, advance the timing while watching the vacuum gauge. Do this with the distributor vacuum hose disconnected from the distributor and plugged. Pull in timing until the vacuum gauge stops rising, then back the timing off to the vacuum gauge's highest reading. Finally, idle it back down to about 850 in park and then see what it does in gear.