Success! I'd think you'd want the secondary blades vertical at WOT for max flow. At 15 deg initial sure doesn't sound like retarded timing is opening the blades to far past a "square". With adequate initial (like we have here) I've never seen that problem. I'm wondering if it's blade/slot wrong phasing if the transition slot was machined wrong but that seems like a stretch & I'm a firm believer in K.I.S.S. but also the secondary link is bent wrong for it not to be wide open so... Wish I had my eddy that I just let go so I could check it out. If you need a 750 rpm idle & will have vacuum you may likely have to tune it starting with using manifold instead of ported vacuum to set your initial then cap it to set the total (slots) then mix/match springs staying just under pinging at WOT