You can upgrade the heads with Magnum or Chev LS valves. 1.88" Magnum or the 1.9" LS. You need to have the guides replaced with 5/16" bronze guides honed to fit the valve stems. These valves come with 5/16" and 8mm stems so they are considerably lighter. With the LS valves, inexpensive LS beehive springs, retainers and locks can be utilised. This can reduce valve weight by 30 grams or more. For this to work the installed height needs to be 1.8".
