tnewland,
I tend to come down on Jerry's side of this argument. The dyno operator is operating the dyno that your car is running on. His job is to use the tool correctly and that requires his attention.
A 6500 rpm pull for a 289 is a walk in the park unless your internals are not up to it - and then you shouldn't be at the dyno! I think you would have to work very hard to make them that weak. What I mean by internals not being 'up to it' is like Jerry said OEM rods, or small capacity
oil pan with a high capacity pump etc. Even OEM rods are amazingly good. I remember during the 60's more than a few of our friends 289's that consistently shifted with ease and repeatability at 7500+ rpm with "OEM" rods.
I think your component failure problem is attributable to the lean period when the engine went above a 16:1 AFR and probably an oiling shortcoming attributable to parts selection or assembly during the build phase. A !6:1 AFR under load is damagingly lean. At the very least it will detonate (which kills rod bearings) and with only a little luck you can burn a piston if you are persistent.
Like someone else said previously, you don't need a dyno pull to diagnose a distributor whoops. You can do that on a distributor machine without even starting the car. Another observation is that when you go to the dyno to do a pull, 150 mph is a walk in the park or a 3 inch stroke engine - so is 7000 or so rpm. Even more significant is the fact that the MPH is not a real consideration. What you are trying to do is cycle your engine through its entire operating range, in high gear, to begin the process of optimizing your tune (assuming you're not there for bragging rights). Wherever the MPH goes it goes! Frankly I don't believe I have seen a dyno that would not accommodate 200 MPH but again the real issue is exercising the engine through the entire operating range in high gear to begin the optimization of the tune.
If I were you I would begin trying to figure out how I got to a 16:1 AFR and fix that problem first so it doesn't happen again. With respect to the crank it is most probably repairable. If not then a modern day replacement is readily obtainable from FRPP. If you are one of those guys who like near bullet proof strength in their pieces have one of the crank grinders cut you a billet shaft.
As a general rule of thumb you do not want to use vintage components with high valuations that are difficult to replace. They are valuable museum pieces today that remind us of how it was during those halcyon years of the 60's when all this magic came into being. They should be on display as historical artifacts to be looked at but not operated.
Just my $.02 - well maybe $.15 (extra words)
Ed