RPM drop and electric fans!

FDNY340 said

Vacuum is one of the issues Im trying to address. No ports on manifold, spacer or Carb.
Was going to drill and tap my spacer. Can you suggest another method??
And thank you for reinforcing the "why" behind the "way"!!

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I would find what the minimum timing it will tolerate at idle first by just by moving the distributor. Make sure the distributor is not adding timing at idle speed through mechanical advance. You could easily add vacuum to the adapter or even the base plate of the carb. Closer to the throttle plates the stronger the signal. Holley? What model?
Here is a problem you can run into with vac. advance and your camshaft. Because your vacuum is low at idle the canister may not fully apply advance or if it does it might be tetering on the edge. This can lead to the "circle of death" as described in an earlier post. An engine with "no power at idle" is unstable and if loaded will drop in rpm. That will cause vacuum to drop. Then the vacuum advance retards timing. That causes rpm to drop and so on.
You could match the vacuum canister spring rate or preload to the low vacuum signal at idle to solve that problem. That could cause another problem. When the rpms raise above idle the vacuum will also increase. Vacuum for motor with a stock cam at idle will raise slightly when the rpms are raised. Vacuum at idle with a cam like yours will raise significantly with rpm. With the softer spring in the vacuum can you might end up with a delayed drop in timing when the engine is loaded to the point of detonation. Sort of a catch 22. Sometimes limiting the amount of timing that the vacuum advance adds can fix this but sometimes not. Beware and watch for signs of detonation or ping when tuning. Sometimes a vac advance is a good fit and sometimes it is not.