I did it when I installed my new Edelbrock heads on my motor before I put them on since it was easier at that time. I have read from some people that say it doesnt make a difference and it might not but if the spark is pointing in the direction of the incoming gasses then it sure couldnt hurt

416 stroker from Nick at Compu-flow. 11.14 in full street trim. Seems like a new best every time out.
11.06 open headers----so far!!