I have a mid 1970 Crane cam catalog that has a chart in it for setting the initial lash on their new cams, the chart calls for setting it .002 loose cold on a iron headed iron block, .006 tighter with a aluminum head on a iron block motor and .012 tighter on a aluminum water block with aluminum water heads
I used those settings on the first all aluminum blown street Hemi gas motor I assemble for a customer, they worked out great compared from the .012 tight room temp setting to the 170F water temps with 160 F oil temps setting on the dyno
My stupid pump gas Duster 400 stroker motor with Eddy RPM heads only changed .001 from hot to cold
The message I got from that stupid motor was to check every motor for what it does, write it down and use it