My built up engine also had surface rust on the bores from sitting
around and had no issues starting up and running it in again but
changed oil and filter after 50kms and 500kms but filter got the
remains with no issues as rings are super thick on A series

My fat stubborn brother should have bought that head of you
when you kindly offered it to him as from last I heard
he was up to 3k now inc buying second hand head.

A Dellows box kit complete with box adds up to 3k
these while 60a dogleg are fetching 2-2.5k in Japan
depending on ratios and condition etc.

All a bargain right there in parts and wagon well forget
about finding a 1200 wagon here for under 8k full of rust.