Manifold Option Parts . Plug-in type, Non plug-in type ( ): EXH block plate Individual EXH spacer: VVFS4000-R-04-1 (Plug-in type) VVFS4000-R-04-2 (Non plug-in type) SUP block plate: AXT634-10A EXH block plate: AXT634-11A Throttle valve spacer: VVFS4000-20A-1 (Plug-in type) VVFS4000-20A-2 (Non plug-in type) Interface regulator/A port regulation: ARBF4050-00-A-1 (Plug-in type) ARBF4050-00-A-2 (Non plug-in type) Interface regulator/B port regulation: ARBF4050-00-B-1 (Plug-in type) ARBF4050-00-B-2 (Non plug-in type) Interface regulator/P port regulation: ARBF4050-00-P-1 (Plug-in type) ARBF4050-00-P-2 (Non plug-in type) Individual SUP spacer: VVFS4000-P-03-1 (Plug-in type) VVFS4000-P-03-2 (Non plug-in type) Double check spacer: VVFS4000-22A-1 (Plug-in type) VVFS4000-22A-2 (Non plug-in type) (172: With direct manual override) 169 Individual EXH spacer (179: With direct manual override) Interface regulator (195: With direct manual override) Interface regulator Interface regulator (195: With direct manual override) (195: With direct manual override) (172: With direct manual override) Block plate mounting position Double check spacer Individual SUP spacer Throttle valve spacer 1550 Series VFS4000