After leaving a trail of ARP header bolts from Denver to Aspen on my first long trip, I replaced them with Stage 8 header bolts. I have an FE so there isn't a lot of room under the hood. They should be pretty easy to install, especially with a 351w. At least you can SEE your header bolts!
I haven't had any more problems and they're still tight, more than 23,000 miles later.
Al