Would it be possible to put together a top end kit together for a supercharged 4.2L ecotech? With ultra high roller rockers lifters, valve springs etc. and whatever else needed?

Yes, we can certainly help you out with that. Please provide us with a list of modifications and what you would like to achieve and we will provide you with a list of required parts. Note, if you’re planning on keeping your M90 supercharger, then I wouldn’t recommend going with a stroker setup.