Hi Dennis,
Slow on my reply to your supplied info. From your most recent posts, I’m scratching my head that all of this is about carburetor jetting…
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In suggesting that you take engine vacuum gauge readings, my first questions were about the movement of the needle indicator at engine idle speed.
Based upon what you have observed and reported at your ‘normal’ idle speed of 500 rpm, I would rule out:
-leaking valves (would see the needle periodically drop 1 to 7 inches at regular intervals if leaking)
-sticking valves / valve guide problem (would see rapid,intermittent drop of needle each time a valve was supposed to close)
-excessive valve guide clearances (would see a low reading and needle fluctuations of up to 3 inches either side of your engine’s ‘normal’ reading)
-too rich an air fuel mixture at idle (would see needle indicator drift back and forth)
-too lean an air fuel mixture at idle (would see an irregular drop of the needle)
Comments:
-I’m surprised that your engine vacuum reading is 11 at an idle of 500. To me, with what I believe an Isky E-4 camshaft grind to be like, this seems LOW. Because of the valve overlap interval of this cam, I would expect the engine vacuum reading to be at least 14 inches at 600 rpm.
Without a damper on the vacuum gauge, the 1 inch swing of the needle that you report with the E-4 cam is probably normal.
However, the 11 you’re getting at idle makes my eyes squint and my face wrinkle in skepticism.I’m of the thinking that the steady but low vacuum reading you are reporting is attributable to:
-late ignition timing
-valve stem to rockerarm clearance settings being too small (I’m sure that in your case this is not a consideration)
-late valve timing
SUGGESTED FOLLOW-UP TEST – Try advancing the ignition timing with the engine at idle. IF the vacuum gauge reading does not increase to a higher number, I believe the valve timing (camshaft installation) to be incorrect.
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My second set of questions was about engine vacuum when the engine was held at a steady operating speed of 2000 rpm.
Based upon the steady vacuum reading of 17 that you reported at 2000 rpm, I would rule out:
-valve spring retainer heights being excessive or not uniform (vacuum readings would fluctuate rapidly if retainer heights were incorrect or different from each other. Reasoning: spring pressures would vary if assembled heights were different, just as if you had weak valve springs. Again, your springs are new and spring values are not in question.)
I’m surprised that your engine vacuum is only 17 at 2000 rpm. Again, this seems low to me.
Once again, I question ignition timing or valve timing (camshaft sync to the crankshaft)
Not reported:
-You did not indicate if the vacuum reading remained steady at 17 or if the needle fluctuated as you increased engine speed above 2000 rpm.
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I did not suggest your closing the throttle quickly at 2000 rpm because I expected that your piston rings are not seated yet. The reading you got when you did this indicates that while your piston rings may not be fully seated, they’re doing their job just fine anyway. 
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I hope someone else will share their thoughts on your engine’s idle speed vacuum reading of 11 and 17 at 2000 rpm. I see Charlie's questioning your low rpm vacuum readings, too.
I’ll be interested to hear how this finally shakes out.
Regards,
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York