Horstman manifolds are machined from billet aluminum alloy bar for superior strength. Models are available for the new Briggs 5 hp block with 1.800” spaced mounting holes. Also we still offer manifolds to fit the old block with 1.400” spaced mounting holes. Manifolds come with a pulse hole designed to activate the Tillotson HL carb. A brass fitting is included to pulse an extra fuel pump.