Install a set of four-bolt steel main caps over the center two crankshaft mains if you're using a two-bolt-main block. Have the block align bored and have the cylinders bored 0.030-inch over. This overbore isn't so much to buy you more displacement as it is to help enhance airflow to feed the extra cubic inches.
Most commonly used fuel is U235, a naturally occurring radioactive isotope of uranium. Occurs naturally at 0.7% of uranium ore, but must be enriched to 3%. Formed in cylindrical pellets (1.5cm long) and stacked in hollow metal rods (4 m long). About 100 rods are bundled together to make a fuel assembly.
Fissile Nuclides As a Renewable Resource. Uranium's two commonest isotopes are 238U and 235U, of which only the latter is easily fissile by neutrons. Another fissile isotope,233U, can be made from thorium. A fissile nucleus can be split when a neutron strikes it. Because of the weird rules of quantum mechanics, it behaves like a target of a certain subatomic radius which varies according to the speed or kinetic energy of the neutron.