I need a sanity check - has anyone else put a vacuum gauge on their 20/22R lately? I've been doing some EFI tuning and recently put one on mine to find it is dancing a little bit. I'm wondering if this is normal for the engine or if I should go down a rabbit hole trying to troubleshoot?

Here it is in action: https://photos.app.goo.gl/TWyi248ZViC8AhGg9

More context:
The engine is freshly rebuilt with <500 miles on it. I took it to a very reputable machine shop near me, and they did a full valve job, checked the guides, etc. I have no reason to doubt their work, as both I and a lot of other people I know and trust have used them many times in the past.

I've checked for vacuum leaks by blocking off all the vacuum ports on the EFI plate and fogging the intake runners with brakleen with no signs of a leak. A compression test on all four showed 145-155 psi on all cylinders. There isn't a misfire that I can tell, as the engine runs great (I'm running an MSD 6AL / magnetic pickup distributor) but I'm still struggling with a small idle surge from the holley sniper and my brake pedal is stiff AF.

Just trying to see if this is just the nature of the engine or if there is a wider problem here that needs to be addressed.

 

See if you can find someone who has a “fogger” or “smoker”. I’ve found vacuum leaks in places you wouldn’t think to look. Brake booster seam was one of them.