How do you get six exhaust pipes out of a four-cylinder engine? The experimental 135 hp two-stroke Model H race engine used a Cummins interpretation of the Uniflow system used by GM. On the block, you can see the inlet manifold lining up with the ported sleeves and inlet ports that were scavenged by a crankshaftdriven Switzer-Cummins blower at about 3 psi. On the exhaust side, the head was the standard H unit, but the Siamesed intake and the exhaust ports were all used to exhale—and that’s how you get six exhaust stacks on a four-cylinder engine. The pump was an updated SD. Persistent rumors state that Cummins tossed this engine into a river after the Indy race. Here’s proof that that is a completely busted myth.