BBC sprk plug gap

[marT350T]

After selling the mid engined polo I have bought a 69 Camaro drag car runing a high compression 468 CI BBC.

It had its first outing at the weekend and alought I was just taking it very steady it ran very well.

After the first run I pulled on of the plugs and found it to be gapped to 75 thou ! I checked all the rest and they were all identical. After talking to the other racers , none had ever seen a gap that big before, so I set the gap to 36 thou. I ran fine for the rest of the day.

Anyone have any ideas why the gap would have been that big ?

[BennettRacing]

No idea, what ignition?

[marT350T]

MSD 6AL

[redvictor]

.025" to .030"

[BennettRacing]

Andy beat me to it, yeah agree, I'd start at .028" and go from there.

[marT350T]

Thanks for the replies. I think my car will be laid up now till next year so when I change the plugs I will gap them to the above.

I still havent got a clue why they were gapped as big as they were

[ribaric]

I had a 515 BBC with 14:1 and tried 25 to 60 at various times. Didn't make a scrap of difference. The idea behind the big gap was to present a bigger spark to get a more positive ignition event. Sounds good in theory but I'd stick to 30-35.