1970 340 Balance Problem...Bottom Line

Fishy, first off, original poster states that engine has original crank.
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"What we have is a 1970 340, with the stock crank and stock harmonic balancer."

Secondly, I think Larry Shepard did a little more than write a book. Let me quote from his book again: Larry Shepard began working for Chrysler as a suspension engineer in 1968. By 1970, he had moved over as staff engineer of Chrysler's drag racing program, where he would guide the winning efforts of drag racing competitors, including Bob Glidden's legendary 340 Plymouth Arrow. He is currently a staff engineer with Mopar Performance.
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So here we have the Chrysler staff engineer that developed the very motors we are speaking of for drag racing, his whole career devoted to Mopar engine performance since 1968, and you don't feel he is a #1 Mopar guru. I find your statement hilarious.