the
55 manual is free as well as the 56 supplement linked above, if you buy one get the 57 or 58 [engine sections the same] full manual and you need nothing else
funny your comment about crazy thinking reminds me of a time I was at a Chev dealer for parts and some young mechs wanted to see the 57's engine - I tweaked the throttle linkage to rev the 235 and one excitedly pointed "look your distributor is loose!"

Bill