I can't find any Nicson manifolds for 2 or 3 X 97, only 3 X 1 for conventional 1 bbl. flange in both side-draft and down-draft and 2 X 1 in down-draft.
Trying for manifolds by type: a 2 X 1 must be a common (plenum) type with simultaneous linkage. A 3 X 1 can be either a plenum type with progressive linkage (idle on the middle throat), or individual runner with all 3 simultaneous.
