I'd go with Stainless Marine or Eikert. They are the best cast headers you can by. They have proven on the dyno at Innovation Marine to make the sale power or more than CMI's. There was a dyno sheet on this going around back in 2000-2001 tesed on a HP500. I had Stainless Marine headers on a Merc 502 MAG and they are easy to put on and will last a long time.