The SK42855 dual four intake was designed by Ford in '69. It was not for T/A use as the C.I. limit was 305ci. It is a little known fact that when Ford Engine and Foundry Experimental Enige Dept did a new "performance" engine developement program, several induction types were made. In the case of the 385 series , a 2v , 4 different 4v's, a tripower, and a dual quad were prototyped. The iron manifolds , (the 2v and 3 4v's) were done with XE part numbers as these were developed by the "production" group. The others were done by the "performance group" using SK part numbers. The 4v design went to Shelby, the tripower and dual quad were made in a small run for dyno testing. Holman Moody got permission to use the dual quad pattern for Marine engines and a few larger runs were made. Those amnifolds carry the SK 42855 part number and were all produced as "small port" versions. When Blue Thunder aquired the Shelby 4v pattern and the dual quad pattern they were updated. The tripower was never reproduced and is on of THE rarest 385 series intakes out there.
Other engines like the Boss 429, 351C, Boss 302, had all four variety intakes developed. Heck even the 351m/400 got a 4v aluminum intake made for it. No multi carbs though.