For the sake of others who might do a 261 rebuild, would you please take pictures of the head gasket, block and head.

You may have a Victor Reinz FS3210 FS7782B head gasket. Since the head has drilled steam holes, just curious, are they angled?
https://www.stovebolt.com/ubbthread...ead/Board/1/main/185946/type/thread.html

Wish I could help with info on the decision for the type valves, seats, guides etc. but I'm always interested in learning.
The worst situation I can think of is hauling logs up Pike's Peak, running E10 on a 110 degree day.
Attachments
261 Head.jpg (76.18 KB, 240 downloads)

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."