Those are the Comptune style racing oversized valve springs, I recognise them, I sell and use them on the race heads, most of the time with roller rockers. Boz to make them work with your stamped rocker arms, you going to have to modify the rocker arms, this guy should know that, ask me how I know /bcforum/images/%%GRAEMLIN_URL%%/smile.gif You have the clearence them on the underside where they are touching. There is no good reason why those springs were used on a street head, they only come into play with lifts well over .500". I would have went for the little Mini Spare .520 HD valve spring, they are a ton cheaper and will handle lifts up to .520" and are the normal diameter. Your valve spring pockets had to be modified with a special cutter to accomdate those larger spring, I done that many times on a race head.