The short answer is "no". They won't be too big. There's a caveat to that though. If you overdo all of the intake and exhaust components before boosting the sir pressure you'll end up in a condition where the air velocity on the intake side of the engine will begin to cause you loose power. I don't know however, the point (or combination) on your particular motor where that will happen. What I can tell you is that I did something similar to what you're talking about only it was Trick Flow heads and not the AFRs. I had enough money at the time for a set of heads and the correct length pushrods. I even used the stock rockers for a little while. Having done just that, I had a noticable increase is power. As I added on it got better and better.
