This has me puzzled:
-swapped spare fuel pump and checked pump rod/lubed
-removed distributor, cleaned, lubed
-removed rear tin
-found one loose sled tin #1
-checked pushrods, rockers
-found a loose manifold nut on #3
-checked pulley (lubed pulley-to-case opening to see if that would quiet it)
after all this, there is still the same annoying chirping noise. It varies with rpm, so it must be something rotational. Could this possibly be something internal, ie. #4 main bearing? Or, perhaps clutch related? Trying to "rule out" the bolt on stuff first, before considering pulling the motor...