The latest I deal with is B20 and B30 but I think with a few exceptions
they will be pretty much the same. Biggest difference is that the later
heads are aluminum. You may or may not want to paint the head.

Since these are WATER COOLED engines there is not too much heat transfer
from the outside of the engine. I am assuming you will NOT be painting inside
the water jacket. Highest temperature of most parts will be in the
neighborhood of the rating of your thermostat except for the exhaust, for which
you will have to use special paint. I have been pretty happy with RustOleum
Rusty Metal Primer and Regal Red. Be sure your surfaces are clean and
especially NOT oily. I usually mask the flange surfaces with wide masking
tape for a slightly neater job. The Rustoleum paint has lasted pretty well
both here in Oklahoma and in Panama. You may need a different primer for
the aluminum head. (It may also be a different color.) I've not painted
aluminum parts this way, only cast iron and steel.
--
George Downs Bartlesville, Oklahoma