Folks,
Well, this has been a true PITA. Anyway, I think the best long term route will be to replace the manifold with the 2101 or 2701 as recommended above and then use the 1406 on that.
however, I have an immediate short term need for the truck and need to get it running sooner rather than later. Carbking, I'm PM'ing you some info to get the rebuild kit.
my learnings: For future reference for anyone in a similar spot, the early style rochester 4-jet ported manifolds will not work without fabricating a spacer/adapter for it. contrary to what transdapt and edelbrock say, their adapters will not work. Transdapt recommended 2304 and that was the same thing as the edelbrok 2696. None of the holes line up to the 1406 thus not allowing the butterflies to open fully. On top of that, there is not a good seal to the manifold.
