This could be a very simple question to some, but in general why can you rev a smaller motor much higher than a larger?? For instance my friends have mostly mustangs and I've driven them. Pushing them (302's) upwards of 6 to 6.5 grand aint nothing big. Where as I don't ever really see many 350'2 being pushed over five and a half. I know nascar motors are reved really really high , but I'm talking about as a general rule. So... how is this????