Over the older LS1 manifold the ls6 Vx S2 ? On gain 20 flywheel HP peak and I think 30 in the guts.
I've got an el CheapO Speedmaster 96mm ally to go on mine. Due to the fact it's bebeen faced had billet rails braided hoses and squirts for $150. These showed 30 flywheel HP gain peak and I think 25 in the guts.
Fast made the most. Was on a street cam set up think aftermarket heads in hotrod magazine years back. Probably round the time this thread was started.