If you want to use a particular game board as a donor board for another game, make sure that the CPU clock frequency is at least as fast as the game you are replacing. Swap out the ROM chips in the top left of the game and plug everything in the same as it was before and the game will operate fine.
The CPU clock frequency for known games is listed below:
- Blitz - 150MHz
- Blitz '99 - 150MHz
- CarnEvil - 150MHz
- Hyperdrive - 200MHz
- NFL Blitz 2000 - 150MHz