Hello, I was wondering if I could get some advice on setting the advance on my 351M. I have swaped carbs a couple times and over the last year been tweaking the advance but the bottom line is I am a newbie and still havent got it figured out.

I currently have a holley truck avenger 670cfm on a edelbrock performer intake. Stock ignition and timing sets (as soon as I get some more money I'll have aftermarket cam and timing set). I have followed the ignition and advance timing procedures listing on Bubba's M-block website. But I have some (probably stupid) questions. The carb has a timed advance port and a full advance port. Wich one should be used? I have used both succesfully, and cant tell a huge difference (except of course they have to be tuned differently). And how do you tell if there is too much advance? What exactly does 'pinging' sound like? With the timed advance setting and a lower vacuum advance sensitivity I can turn the dristributor all the way till it stops and the idle speed is still increasing/holding steady. But the engine becomes difficult to start... once its started it runs on slightly more 'rough' than a much less drastic setting.

I guess it would probably make things easier if I could read the actual advance degrees but there appears to be no marking that I can find on my motor to tell you the timing degrees.

Any help is appreciated!

 

You'll get diferent opinions on this but I like to keep it simple and use full time vacuum. The enigine likes a lot of initial advance and with stock compression you can keep easing it up till you get a little kick back when starting after warm up. That's a little too much. You problably cannot make it ping.

 

Thanks Beartracks, I am currently using the timed spark port on the holley truck avenger, and have it set just before it becomes harder to start. I might switch back to full vacuum and retune. But first I need to get an oxygen sensor to figure out were my mixture is. Its just too hard to shoot in the dark without being an expert at this yet!

Something else I read somewhere is that ford used some kind of delay inline with the vacuum advance because it would 'spike' when the throttle was changed quickly from a steady state. I wonder if I was having the same problem because the truck avenger seemed to have lots of idle power but yet sometimes it would just stall out when I stepped on it, especially going around turnes and when the c6 hasnt downshifted yet. Plus the truck avenger is supposed to have some kinda vacuum booster to help idle and accelrating vacuum. With my last setup using full advance I got 20" vacuum at idle witch to me seemed kinda high but I dont really know if too much vacuum means anything or not.