I wasn't making my intake adapters when I did the dyno testing for the book, so its not in there. But I have heard from several folks who run them that they really work well, although the Edelbrock 2863 manifold with the Dominator flange is even better. Note that the 2991 intake has to be machined to fit my intake adapter, and you have to have the Yates style adapter (part number 13006), not the standard 13001 adapter. Also, some port matching between the adapter and the 2991 intake is required.