Spark plug reading for timing and correct heat range

[tommytmopar]

Great charts.

 

[383man]

I agree vacuum advance is very good to run on a street car but I don't run a vacuum advance on my 63 because my dist don't have it. I got a great deal on a Mallory race dist and that's what I use on my 493 and the car runs awesome on the street. No matter where I hit the throttle its instant go. I run about 22 initial and 36 total and it works very good on my car. The eng has been in the car and running fine like that since 2011 and still working good. On my carb I use an 850 Holley DP and I set the primary lean enough to cruise the street and not foul plugs every few weeks. I worked my IFR and transfer slots and jetting on the primary side to run good and clean as that where 99% of my street driving is done. Then I jet the secondaries for mph at the track. I also open up my primary power valve channel to give more fuel in the primary at WOT. Its worked great for me in my setup as I can drive all summer on the same plugs and not foul any. And then go racing with the same plugs that have been in it all year and run fine. But you have to have the carb set up so your not way to fat when driving on the street at part throttle. Good luck with it , Ron

 

[justcruisin]

That is exactly how I have set my carb up, work the primary's/IFR's to get a clean cruise and tune the secondaries and PVCR's for power. My PVCR's are almost as big as my primary's. The experts say you should work on about 25% pvcr's/primary jet but that is not what works for me.