I'm somewhat new to engines and I was wondering, when one gets their heads ported and polished do they need to get new rocker arm's? I could be mistaken but the way I understand heads it just seems like you would if you went too big with your porting. It would also seem that with ported heads a new camshaft might be necessary. Also, another term I've seen on some other automotive sites is a Valve Job. What is a Valve Job? I'm pretty new to performance engines and whatnot and I want to learn this stuff.