These pages discuss flatheads for the Model T.  Head design discusses compression ratio and head design and their effects on engine performance.  Dyno tests presents the horsepower and torque for various heads.  Head photos contains a photo gallery of accessory Model T heads.  Dyno test photos shows photos from our field trip to the dyno shop in Oklahoma City.

The graph below summarizes our best estimates of head performance.  It is a combination of dyno tests and calculations with an engine simulator.  All results are relative to a stock unmilled high head.  Blue indicates peak torque and red indicates peak horsepower.  The solid lines are from the engine simulator and the symbols are from our tests on a chassis dynamometer.  Both the Waukesha-Ricardo head and the Z head perform better than the engine simulator predicts.  We believe this is due to the improved squish style combustion chamber.  The dashed lines estimate the performance of a squish style head with various compression ratios.  As you can see, we would predict that a squish style head with 6.2:1 compression ratio would produce 50% more power (30hp) and 34% more torque (111 ft-lb) than a stock head.  If you want to understand how this will effect the performance of your car, look at the Power and Torque page.