You should tear it down and do a complete stroder rebuild with nothing but the best parts money can buy. Rebuild the plow setup and have the frame powdercoated while you're at it. Or...
Had that happen to me once. The lobe wasn't round yet, so I just tossed in a lifter and went on my way. It was a beater and lasted a while longer (until I got rid of the car, actually). A few quick oil changes might get most of the mess out of the engine if you're lucky.