Castillo states, "If you decide on going the naturally aspirated route, then modifications to the rod (2 mm on each side) similar to what was done with this project motor is ideal. If it's a high horsepower motor, then it's recommended that you open up the rod journals by cutting out 4 mm on the crankshaft. Our initial goal with this setup was to experiment on the rods themselves by lightening up the rotating mass on the engine and further expand our testing for this engine on a street turbo motor application. If you grind the crank, then it's possible to use all Prelude components." Here's a close-up image of the machined H22a end cap fitted with a K24 rod bearing.