If you are looking to buy check out the 4mm top end in the for sale section. They come with the valves, and he is letting them go for a very nice price. With powervalves you will get more bottom than any cub will ever think of having( yes a cub can be set up for lower power but it will kill the top). As for cubs vs cheetahs most drag motors get the powervalves blocked off. So as long as it is the same bore and stroke there is very little diff. asside from larger intakes. It is all going to come down to set up!