^^
The V8-6-4's main problem was that its computer wasn't up to the challenge of controlling it. It was a brilliant concept but the technology just wasn't there. I think if they'd had solenoids to turn off the lifters instead of solenoids to disengage the valves' rocker arms
it might have worked a bit better.
I think every single 8-6-4 I've actually clapped eyes on had had its modulation system deactivated, and the engine was locked into a V6 configuration. That's only been about three cars, but there it is.