Help -- Old Fashioned engine tuning with vacuum gauge

[gigamanx]

Hey all.... I gave up trying to guess my way to a good tune of the chevy 350 engine. Craigslist uncovered a kit with timing light, vacuum gauge, and a 7 function analyzer. I've watched a few youtube videos trying to learn how to set timing.

The problem: Engine is running rich because I get "run on" or dieseling when I turn the truck off. Just a few seconds, but I'm pretty sure that's bad. I dialed my carb all the way in on the idle screws and I can smell the richness in the exhaust gas smell (no color just smells oily). There doesn't seem to be a way to get it any leaner. Edelbrock 1406 carb right out of the box, so no needle changes or springs just yet.

Low idle, the engine feels rough...when I accelerate, no problems. Sounds good and feels good.

I'm asking the more seasoned tuners among us to help me understand how to set timing and lean/rich mixture. I can't see the timing marks because there is a water pump and power steering pump right where the zero mark is, so that's basically useless. I read somewhere I could do this with just a vacuum gauge and the RPM marker on the 7 way analyzer.

So far so good...I have the timing set where I get a consistent -30 on the vacuum gauge. Not sure if that's good bad or otherwise. If I retard or advance, I notice the vacuum drop slightly. So, I'm pretty sure I'm with a couple of degrees of "correct."

The rpm is set to 1000 rpm at idle which I understand to be too high. Supposed to be around 600rpm right? If I adjust the idle screw that low, the engine doesn't want to idle. Very rough.

Question 1: Is that the right way to do timing?
Question 2: How else can I make the carb leaner. I didn't seem to have as much of a problem until I installed a phenolic spacer between the carb and intake manifold. I did install the correct gaskets. I would think I would have a lean issue not a too rich issue.

Brand new carb, brand new gaskets, brand new intake manifold.

Any help is appreciated!


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