I gotta tell you, I bought a 413, new build, tunnel ram, dual quad engine on a stand at an auction for $650. That’s something you’d like to know more about the internals instead of opening it up. It came with a 3 ring binder full of all the information about the engine. The guy had things in the book on every page, 3 different cams he researched and their specs, cost, and where he found each one, then he circled the one he installed. All through the binder you could see how he was putting together this engine with like minded part for the purpose he wanted to use the engine for. It came in very handy, I sold the engine because I didn’t need it, but due to the info included, the guy that bought it wanted to use it for its intended purpose.Great advice here and that’s what I have to add to my projects as I do them (a timeline priority)