i have a stock 425 on my 78fwb w/the hei dizzy and such, and yesterday when i was getting out of the snow on my street, my spark plugs fouled. this isnt the first time i've fouled em out by running high rpms for a short time. and its never the same plugs either. any clues as to why this is happening? i have my mixture screws turned way down on the qjet, to no avail.

thanks for looking.

anyone?