Depends on the engine. Some have great low end, some scream to the moon (top end). There are very few with good amounts of both, and of course those are the very expensive mills (think Ninja, RB C6BBT7, etc). If you want acceleration, look into the Novarossi P5X, it's a low end monster but still with a decent top end and it won't break the bank. Incidentally, it's the latest evolution of the engine that was in the car in the famous house-jumping video. It's a big block .21, which means it won't fit into a 1/10th car without modification to the engine mounts of the car. It will drop straight into any 1/8th model though. If you're thinking 1/10th, there's only one small block with the characteristics you want, and that's the OS 18TZ, modified it can be made to compete with the really fast big block engines (in a lighter car of course).