Put compressed air into the cylinder. Do it straight from the compressor not via a ball valve or Tire gauge. Had it loose comp and nearly dropped a valve.
You’ll have to make a tool to get valve spring on and off.
Nothing is impossible depends how much time you have as fiddly.
If you decide to pull the head off chase a VRS kit first as they’re getting hard to find now. There’s a few in Oz on eBay. But abit pricey.
Hope this helps
BP