I built my own Weber adapter plate out of some 3/8 aluminum. Cut it to shape, cut the opening, drilled and tapped it for the carb studs. It wasnt that hard, Im sure one could be built for the holley flange. I then had my good friend tig weld the plate to my intake. He also tigged up the unused vacum nipples and egr valve holes. Heres a couple pics sitting on my mock up engine (still need to clean up the welds and powder coat it).