I believe it is an aftermarket intake for the '53-'54 Chrysler 331 hemi. The bolt pattern is the same and it has the water outlets in the proper location. The pre-1955 early hemis had a "wet" intake with the thermostat housing as part of the intake. The later hemis(late '54-'58)had a crossover manifold that held the thermostat and bolted to water exits on the front of each head. This one has the water outlets in the same location as the early "pre-'55" heads. It's a very unique manifold and probably worth $$$ to an early hemi enthusiast.