Want to know what kind of total advance is best for my 400. It must already have the lighter springs in from a previous owner cause it max's out at 20 degrees under 2500 rpm with the vacuum plugged. I'm running about 10 degrees intial giving me 30 total. should I flip that piece around under the plate in the distributor to get 30 mechanical out of it and cut back on the initial as fuel may dictate? I also have the adjustable vacuum can to put on it.

 

I have the advance specs for all of the old distributors but nobody seems to have a part number listing that tells which distributor went in which engine.

Somebody has to have a micro fische for Ford cars back in 71.

 

Sounds like your pretty much where you need to be. I would bet if you went with the longer slot you would hear some detonation. You can grind the short slot until you start to hear detonation & then weld it back some. But I don't think it would be worth the effort.

 

Is this in a street car or truck, And what are you doing with it?

 

Street 4x4 with 9:1cr headers, intake carb cam. Made as a for fun driver, not off road or towing.

 

I have about 9.7 to 1, and have no probelms with timing, in a 351M.

 

74 F100 351m, you also have a bigger cam and we won't even mention the words "fuel economy"...

 

I have been running 34 degrees total on my Mallory Unilite, but I ran an analysis on Engine Analyzer Pro and it told me that I could be detonating at 4500 RPM with my CHI-3V fast burn heads. This is where my VE gets to 114% and the cylinder pressure is maximum. I just reset the mechanical advance back from 24 degrees to 18 degrees. I want to keep the 10 degrees initial.

Fast burn heads do not need as much advance as conventional heads. I ran 34 degrees total all the time I have 351C-4V heads on it.

I used to get some pinging with the 4V heads in CA with 91 Octane in warm weather, but I have never heard any pinging with the CHI heads, but now I use 93 Octane. Of course my cam keeps the cylinder pressure low at low RPM. I am not really sure that the analysis is correct and I get 114% VE, but since I have fast burn heads it will not hurt to reduce the total advance.

I guess that this has gone a little astray, but If you go onto www.performancetrends.com and download Engine Analyzer Pro, you can get a trial version. Use it to simulate your motor and you can adjust you advance curve and your total advance to determine the best place to set it.

 

Torque1st beleave it or not it gets 12-14mpg then I'm not standing on it. With 389 gears and 33 inches of rubber. But it will only burn 93 octane.

 

I run pocket ported Ford heads. A hi speed towing cam and offy intake and a 750 Holley. My advance is set for 18 to 20 inital and around 8 at the distributor total timing 36 degrees. I back off on the inital say down to 16/18 for poor quality gas closer to 20 for better grades. I attempted to use vacuum advance but with out EGR its almost impossible to have it dialed in well. I currently get 13 to 14 MPG which could be much better but I have a 3000 RPM stall converter. It would be closer to 20 MPG but there is about a 25 percent slippage at 60 / 70 MPH. 4.11 gears 33" tires 4x4 is a 8' bed 78