429 vanilla? Never hear that one. The 400 never came with a factory 4 barrel. Ford's go to spread bores were the Autolite 4300 series and the Thremoquad. The 4300 was used on the Cleveland engines and the Thermoquad was used on the 460. I think there was some crossover for the 4300, but I've never seen or heard tell of a Thermoquad on anything else Ford, but the 460.