When you install headers on an F or 2F equipped Land Cruiser, you lose the stock heat riser, making for longer warm-ups, poor fuel economy, and rough running. With Man-A-Fre’s Fluid Heat Riser you not only eliminate the long warm-ups and running problems associated to a cold manifold not properly atomizing the fuel mixture, you also no longer are hitting the bottom of the intake manifold with crack causing exhaust gases. For those of you living in cold climates this is an essential item for proper running with headers. For 1968 through 8/87.