A Viper engine was built as a high-performance engine. I.O.W. it was built for performance use.
One HP per cubic inch does not place it in a highly-stressed performance engine category.
Part of the success of certain engines was due to the combination of being overbuilt AND not generating enough power/r.p.m. to hurt themselves.
Keep the 8.3L full of clean, high-quality oil and maintain it and it should last a long time.
Unless you are bouncing it off the hard-limiter every time you drive it, running it too low on oil, etc; it should last just as long as any other engine. Driven conservatively, maybe even longer.
Have it tuned or have an engine rebuild done by someone that doesn't know what they're doing, and all bets are off.
Have fun