Still have the C3500HD and it will stick around as the backup vehicle since it doesn't have a backseat or 4x4 capabilities.
Picked up this truck over the weekend. 454tbi, nv4500, 4x4, 4.10 gears all stock even on the 215/85r16 tires. Trans was recently rebuilt or replaced and the engine runs well with the common 10mpg cruising at 70mph hauling the motorcycle. Rode down to the border, bought the truck and drove it back.
While I prefer a diesel engine have had 454's before with little issues...