Plug gap with MSD 6al

[wedge5]

Should I open up my plug gap more with the MSD box? MSD says you can go all the way to 55. I have mine at 35. Should I do a happy medium and go with 45 and then pull the plugs and see what they look like.

500 MW 650ish HP runs on 93 octane but race with 100. Mostly a strip car.

 

[moparmarkk]

at 55 on my car,black and fuel fooled,45 nice and tan.run 93 octane with lucus non street booster.20 runs still tan plugs,mark

 

[mark42202]

I agree with Mark. 45 is a very good place to start. If you're racing, put new plugs in before the pass, then shut down after the finish line and get towed back to your pit. If you drive it back to the pit, you will not get an accurate plug reading!!

 

[wedge5]

Will do.

Never thought about it before but on my mild 440 I had them set at 55 and the plugs were black and fuel fouled also. I also ran a sbc Chevy dragcar the same time I drove the Dodge on the street. I only ran the sbc at a 40 gap. I just thought since the sbc wasn't as beefy as the 440 that the gap should be smaller. I never had the plugs foul on the chevy. Now I know why! I never put two and two together, guess you learn something new everyday!

 

[68X426]

With my Hemi (highly modified to 505, aluminum heads), I experimented with 35 to 60. Found that all the plugs were happy at 49, so 49 it is.

 

[SUPERSTOCKRACER]

it all depends on your compression. less compression less gap.