Putting DOHC pistons in an SOHC engine in a Dodge Neon has be performed. The two engines have essentially the same block and crank except for the PCV system in the '95 SOHCs. DOHC pistons raise the compression a little less than half a point. The DOHC engine actually has slightly less compression than the SOHC because it has 54cc's of combustion chamber volume. The SOHC has about 48cc. Therefore the DOHC uses slightly domed pistons to increase the compression.

If placing a DOHC head on an SOHC block is desired, it is much more affordable to purchase a DOHC donor motor. Otherwise, the project expenses will accumulate very quickly due to having to get the manifolds, throttle body, sensors, some timing belt drive components, and wiring harness to get it running. A DOHC computer will also be required to get the right fuel and spark. The fuel and spark tables are completely different because the two engines have different airflow characteristics.