Most of those early eighty's cars with the V8-6-4 had it disconnected and just ran in the regular 8 cyliner fashion within a year or two. The ones that didn't, died. Most of those engines failed because the uneven temperatures in the motor from the non firing cylinders would warp the heads, and even the blocks. It was a good idea that was too far ahead of it's time. Nowadays it's been fine tuned to where it's more reliable and less of a problem waiting to happen...
As for the Impala's. It's no harder to work on than a G-body. It's still a body on frame platform, which is essentially the same chassis since '77. The LT1 and L99 engines are incredibly reliable, and I know of original oweners with 120K mile motors that took them apart for build ups that still had cross-hatch in the cylinder walls. There are a few quirks, like the Opti-spark, squeeky door panels, and digital instrument clusters that fail, but thats about it.
As for the Impala's. It's no harder to work on than a G-body. It's still a body on frame platform, which is essentially the same chassis since '77. The LT1 and L99 engines are incredibly reliable, and I know of original oweners with 120K mile motors that took them apart for build ups that still had cross-hatch in the cylinder walls. There are a few quirks, like the Opti-spark, squeeky door panels, and digital instrument clusters that fail, but thats about it.
