Vacuum advance question

#1
Question: Finishing up my 409 build and was wanting to utilize one of the Demon carbs I have on hand. I have always run Vertex mags on my SBC's so never had a need for vacuum ports. I will be using a vacuum advance HEI, unfortunately none of my Demons have vacuum ports. I will be using a 1" composite spacer between the intake and carb. If I driil and tap a vacuum port into the spacer, will it provide enough vacuum for the advance?
Thanks
 
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