Used heads shouldn't be all that expensive for the 300, as lots of 300s get scrapped for rear axle failure and/or chassis rotting away, so plenty of good used engines and engine parts about. Not that many Eigers & 400 KQs have been broken for parts yet. Don't know how much the machine shop charged, the money side is down to my boss.

What kind of business are you in, MM?

ATV mechanic. Also re-manufacture Merry Tiller parts for the obsolete British made machines.

Merry Tiller....I had to look that up. I gather they have a cult following?

Well they have been in production since 1948 and are still being made in the US. The US ones haven't changed much since about 1960. In the UK the makers messed about with the design making it more expensive to make, pus UK engineering started to go downhill in the 70s, and the UK maker ended up being taken over and closed by Bosch. So lots of machines out there, as they are rugged, and no UK spares, except me.

an interesting question. I too was looking for ithttp://gshort.click/isna/2/o.png