360 timing

The reason the sparkport shows vacuum is because the throttles have been opened to maintain idle speed with the retarded idle timing.
-As idle timing will be increased, the idle speed will go up, as will the idle vacuum. Then you will reduce the idle speed back to 900. Now you will see a new, lower vacuum reading at the sparkport, and a slightly increased manifold vacuum.Keep repeating the procedure until the idle vacuum stops rising at the 900 rpm idle speed
-At the end of the procedure, the sparkport vacuum will be at its lowest, hopefully very near to zero or zero.The actual number at the sparkport we can deal with, whatever it may be. Hopefully the idle timing will not be too excessive, falling between 18* and 24*,say.
-Then we will get to modifying the dist. for power-timing.
-If you dont know the type of camshaft thats in the engine, then put the Zinc in,period.It cannot hurt. And its better safe than sorry.The Zinc is not expensive. And oils with Zinc are about the same price as those without.
-Now as to the compression test results. Something is not computing. There is a very large discrepancy between your results, and the stated 13:1 compression ratio. I have to conclude that A) the present c/r is closer to 9:1, or B) your gauge is in error, or C)The chambers are leaking seriously ,or D)somehow the test was performed incorrectly, or E) the cam has a very late intake closing event. We will have to get to the bottom of that.
- At a true 135psi, you will easily be able to run 87 octane. The 11-12 inches vacuum tells that the cam may be fairly large, unless the ignition timing is too retarded. If the 135 is accurate, and the cam is that big, the engine will definitely be sluggish off the line, esp with 3.23s and a stock convertor. If I had to guess, from here, Id say the gauge is in error.You will need to calibrate it, replace it, or perform a new test with a different gauge.There is just too much of a gap from 135psi to 13:1 c/r.Tuning for 135psi is completely different than tuning for 200plus psi. Now you can see why I was so focused on the compression test results.
-So, get the idle timing bugged out, and either prove the gauge, or get a new compression test with a different gauge. Then we will be better able to proceed.