Vaccum reading is a result of how an engine is running. It's used to set the carb. It is not used to set timing...lol. Usually becuase the end result is exactly what you have..it's too far advanced for the starting system to run with after trying that approach. From what it sounds like, you have the easy to change parts on that engine. It will run witht hem, but you'd be happier if they were all matched. First, the cam should be at least a stocker from a 4bbl engine. 318s never came that way until the late 70s, and then they used the 360 4bbl grind and heads. Summit makes anice cam for little $$, I'd suggest you replace the cam and timing set with the Summit brand replacements. Second, your distributor is curved for a factory 2bbl. You are adding performance potential with the parts, but if the ignition is not similarly addressed, you're not getting that performance out of them. A set of performance springs can be had for under $10, Mr Gasket and MP make them. If you can score the old (now discontinued Crane adjutable advance kit off Ebag, it's a great pckage. The last 2 I bought cost me $30 each. The springs will get the timing to rise faster, but the limiter of the "centrifical" advance is done with the slots in the plate that the weights are hidden under in the distributor. All the plates are stamped with what they have for max advance. Most will be in the 14-28* range. You want to limit the centrifical advance to around 18-20* if it's way over that. You do that by welding or brazing the slots to make them smaller. I've paid about $20 to a local muffler shop to have this done. If it's stamped 24*, and you want 18, then 6* is exactly 1/4 of the slot length. Have them weld that amount, trying to keep the weld clean, not all snotty. You 'll have to dress the weld with a file to make sure there is absolutely no binding in the weights. Then, put it all back together using one light spring, and one heavy spring from the pkg. Using a $5 timgin tape, and your timing light, set the total ignition advance (with the vaccum advance disconnected and the line to the carb plugged) to 35*. That's set witht he engine at at minimum 3000 rpm. When it comes back to idle, that should be around 17*. The combination of the cam, and the correct timing curve for a performance engine, will be like night and day, and the engine should start with no problems at all at 17*.
Or, you can just buy the MP performance distributor, and follow the instructions to set it properly. This method takes a little effort, but saves a couple hundred bucks. Once the timing curve is properly set, you can then use the vaccum gage, and first set idle speed to about 650-750rpm, and then set the mixture up with the gage.
