Gearing, probably.

It's already been done. We know it works, it's just pointless. Why not team with a company like Solazyme and get biofuel that's actually being produced from algae (no plowing fields, I'm not going into how many ways it's green, but it is) and provide some real world numbers. Like this:

The Cummins 12-valve was available as the diesel engine option in the Dodge Ram for a lot of years, with newer versions being used after 98, and even newer versions in use since 2008. One advantage to diesel engines is they have longer service life than gas engines. My BIL has a 92 ram with the 12 valve in it, and he makes his own bio diesel from waste oil, which he doesn't steal, he gets legally. For a rough comparison, he gets about 23 MPG on dino-diesel, and 21 on Bio-diesel. While pulling a horse trailer. For further information, check out the DOE's energy density numbers, which will prove the bio diesel is much more worth while than, say, ethanal.

Additionally, bio diesel exhaust fumes are nearly entirely non-toxic, the amount of material harmful to humans or the environment is ..well, probably less per mile than per toy imported from China.

As far as modifications to this engine to run vegi oil, I know guys with 12 valves that run soy bean oil for fuel, and they just have larger fuel filters they change more often. I can't imagine it took much to get to where those kids are. They need some serious direction.

I used to work for a hosting company, and the FBI was interested in plenty of our customers. They would show up with a warrant for information and explain that we could either provide the data they needed, or they could seize the equipment the data was on. I wonder if the host failed to comply with a warrant requesting data?

cellulosic ethanol is not a clean energy source, it's a bad idea. It uses food crops or food crop capable land to grow something that won't be used for food, so it cuts back on food production, causing price increases there. It's also energy negative, which means it uses more energy than you get from using it. Look at the energy density of gasoline vs. ethanol. Your cars will get less milage burning it.

You know what the answer is? Biodiesel. Algae reactors can use waste water and ultimately clean that up (solves a problem) and be set up anywhere they can get sunlight (not using crop land) and biodiesel production is energy positive. Add to that, there is a smaller gap in energy density between petrol diesel and biodiesel than between gas and ethanol, and you're moving in the right direction. Things get downright warm and fuzzy when you remember that compression ignition engines are more efficient than spark ignition engines.