Attempting to get ready for installation of Fenton headers on a 235. The stock exhaust manifold bolts to the intake manifold at the heater box. If I elimate the stock manifold for the Fenton headers I have a fitting in each header for a tube that should go to the intake manifold for heat. Anyone know how and where they hook into the intake manifold heater box. Does the heater box need a bottom w/ fittings in it? Anyone have experience w/ this one?? Thanks in advance!!