Plug reading
Car seems to run well, no surging or popping. I just thought that they looked a little grey as compared to tan.
Stock 68 340 with 71 J heads with a mild cam, similar to a 68 four speed cam.
18* initial and 34* total.
3310-1 Holley with stock jetting
72 front and 84 rear.
Overall for mixed street use, they look OK to me. See a little richness at initialtion on one side of 2 and 4 but not the other. Same w/ 7.
There's reading plugs for problems.
Problems would be things like melted or severly worn electrodes, bad fouling, etc etc,
Then there's reading for tuning which is a little different and what you're asking about.
Really need to know the conditions the spark plug and then put that together with the evidence on the plug.
3310-1 has downleg boosters and spivies on the primary boosters.
The spivies are to redirect (balance the fuel) distribution in its original application - and may or may not be helpful on yours.
In normal daily driving it won't make a noticible difference. On the interstate - maybe, and on the drag strip or more extendend top gear wide open throttle - probably will.
Stock secondary jetting is 76 and the secondary power valve was an 8.5. Secondaries really only come in to play during high speed passing and quarter mile, etc.
All that is mentioned to illustrate how the use plays into what is seen on the sparkplugs. If those plugs are showing 3 quarter mile passes, thats different than if its show 3000 miles of mixed street use.
