A couple points from the 232 SAE Paper

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I bought the full PDF of the SAE Paper for the Torque-Command 232. I know I cannot post up or share the paper publically, but I think I'm allowed to talk about what I paid to read. 

The first page had some bullet point goals for the design of the engine, and all of them were met according to the author-engineers: 

Performance comparable to moderate displacement V8s on the market.
Operating smoothness and quietness equal to modern V8s.
100,000 mile design life; production engines must pass a 500 hours full-load endurance run at 4000 RPM. 

Woah. Think about that last one: 4000 RPM at full load. With average gearing, that's roughly 100 miles per hour, which would also be roughly top speed and therefore full-load for the engine. The engine can sustain 500 hours of that and "pass" their test. I don't know what condition the engine had to be to "pass" the endurance test, but I pressure it was still running decently well if not to its original standard.  

Basically...you can run your 232 for 50,000 miles flat-out floored at its top speed for 50,000 miles and it'll still be running anything from halfway decent to perfectly fine by the end of it, and that was a specific design goal for the engine that was actually achieved according to this paper written by the engineers themselves. 

They also had 10 test cars, each driven 100,000 miles in real-world testing for a total of 1,000,000 miles. 64% of the driving each car was either on a turnpike at 70 MPH or a test track at 80 MPH. The first engine to hit the 100,000 mile mark did so without needing its cylinder head or oil pan removed.
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Other points:

Remarkable detail was placed on crankshaft design and balance to produce a truly smooth engine. A 4-counterweight crankshaft was developed and tested. It was deemed adequite for standard six-cylinder practice, but inadequate for the goal for smoothness and bearing life on this engine. It produced some bearing loads and vibration due to not being fully counterbalanced. A 12-CW crankshaft was considered since it is fully counterbalanced as a whole to produce zero bearing loads or vibration and also individually balances each cylinder to reduce crankshaft stress, but was deemed excessively expensive to produce. They instead compromised on an 8-CW crankshaft, which is also fully counterbalanced and produces no bearing loads or vibration, but produces slightly higher crankshaft stresses compared to the 12-CW version because each cylinder is not individually balanced. It's still significantly stronger than the 4-CW version, which was already deemed perfectly adequate. It's interesting to note that the 258 eventually received the 12-CW crank before downgrading to the 4-CW. 4.0L's used a 6-CW. 

The engineers note in the paper that EVEN MORE smoothness could be achieved by counterweighting the crankshaft to compensate for rotating end of the connecting rods, but this was deemed completely unnecessary by all driving impressions, as the 8-CW crank already produced "an exceptional degree of smoothness which was fully acceptable to all concerned." 

Also: respect the stock log-type intake manifold. The engineers tried some high-flow, ram-type individual runner manifolds and provided pictures of them. They resemble the Chrysler slant-6 manifolds and many of the aftermarket manifolds available for these engines. They produced HORRIBLE fuel distribution and cold weather vaporization problems, resulting in poor power and drivability. The air-fuel distribution chart for the log manifold actually shows exceptionally good fuel distribution, beating out all other designs by far. 

I love this engine. What a wonderful design. 