I think at this forum there are only a few members who have gone to that extent that have made any changes with cams or cam timing. At earlier years ktmperformance.com had even a kit developed but that is out of sale for already a long time.
For what I suspect from high left/long duration cams is that without replacing also the valve springs that is a recipe for expensive repairs as the OEM springs seem not to handle even the raised RPM with the stock cam, have not jet investigated what would be the more racing suitable single springs that fit 390 but for sure would like to get a set of these to be on the safe side.
Don't get me wrong i don't race by the way. But i think you won't be needing a camshaft for track racing, you could but as far as i know it goes hand in hand with valve springs + retainers. I've seen gray area KTM have these titanium springs + retainers available.