A custom head + rotary valve train, the EJ25 uses standard valves with a standard cam design, this is fine, but rotary valves have their own advantages and disadvantages that I think would be fun to tinker with. Unlike a regular valve, rotary valves don’t have springs, therefore they don’t experience the “valve float” that standard valves experience at higher RPM’s, allowing you to rev to very fast engine speeds. They also give better fuel economy since they are much lower resistance, standard valves have to overcome the force of each spring in order to open, rotary valves are just a hole. Rotary valves are also non-interference, and if I blew the timing belt, it wouldn’t destroy the engine
I’d also just like to be able to make shit out of metal, it’s a brainworm of mine I’ve had forever
Can relate, when I start infodumping or talking in depth about stuff I enjoy I can see their eyes glaze over and they want to leave.