If you have a ported blower with a decent pulley combo on it I would run NKG TR7ix plugs at 0.030 gap. Try the gap and see if you get blow out, you can always tighten it up if you need to.
BR7EFs will work for you if you want to go the copper route. Plus the porcelain is really sunk down into the plug, protrudes less than the 7IXs.....call it a little extra protection