LOLOL, good response to my askew view! Yes, technically they are single plenum, but most cast tunnel rams only have a relatively narrow passage connecting the two plenums. In these, there is more pressure equalization through the connection than any significant front to rear or rear to front flow reversal of mixture happening. So in an over simplification of this I stated dual plenums, because there is some separation of mixture flow of the front carburetor to cylinders 1,2,3, & 4 with the rear flowing most of the mixture being fed into 5,6,7, & 8 cylinders. Probably not so much in the bigger competition V bottom plenum cast or usually sheet metal pro stock type intakes. But, the positioning of the carb venturis above the top of each runner (albeit on top of the plenum) has some significance. Ever notice most tunnel rams will have a few or all the runners angled to do this? Same reason split Dominator type carbs were developed for use on the mountain motor builds.
