Hey there, I have been messing around with the Idle mixture screws and setting the highest RPM/Max Vacuum but I think my spark plugs (NGK UR4) tell me its too lean. Gap is 0.03 The 350 has been rebuilt (20 over) and runs smooth and not over 200 degrees on a 92 degrees OT day. The Rochester 2GV has not been rebuilt( Winter project). Some plugs look very clean, others light beige. Is this something that needs to be adressed or am I beeing paranoid? Thanks in advance Oliver
Not much of a gap on the plugs. Points? HEI? The link isn't going to be much help. It's for drag racers. Only useful if you do a WOT run, shut it off immediately and pull the plugs, not very practical. You best bet for tuning NA , would be an AFR Guage. Perhaps you can borrow someone's. Jim
.30 is over a 1/4 inch wow those are big plugs LOL. 0.03 is correct 30 thous. The plug chart can be used for non race since the "J" strap can be used as a guide for the heat range Take a closeup of the top of the plug and send pic you will see. I would show pic but my pics from my phone are not in computer yet. I do have one NGK Yr5
How many miles do the plugs have on them? Type of driving? Most plug reading "instructions" I've seen assume jetting for max power and wide open throttle. It can take some miles to color new spark plugs in healthy engines on the street.
