I'm with Patrick,
I would like to know what the "brick wall" is with the v10.
While it could be the heads (I have seen modded LS1 heads flow more than modded Viper), surely no intake alternatives (but these could be fab'd), and maybe it just comes down to the ECU (they just don't like rumpity-**** cams)
And then it could be the owner profile combined with production numbers. Viper mods are usually done by "tuners" and not in one's own back garage. I mean, how many owners have pulled their heads off and started porting their own heads? While this has been the method a lot of fast private Chevy guys got real fast, this doesn't seem to be what's going on with Vipers. Too few do it yourself racers, too few speed parts, everything is way too expensive, ... the deck is stacked!