You don't have to, but those two items together should give you quite a bit of insurance.
The theory about the dampner is that the crank whip damages the bearings. This has been proven by Terry Haines.
Also, what we aren't sure of, is this: Is it a combination of crank whip and oil starvation? Does the Crank whip damage the bearing, making it overly sensative to oil pressure fluctuations?
Another variable is the specs on the crank and block where not to tolerance on some engines. There might have been some blocks that where destined to fail from the factory. We will never know unless we can go back in time and whip out some Plasti-Gauge for the bearings.
What was the final diagnosis of your engine? Any pics of the spun bearings? A proper autopsy can be done by Terry if the block is still around.
