I don't think you will see much, if any improvement with just an intake and carb. The stock cams are rediculously small. Cam, intake and carb that compliment each other will be the next step. If you have time there is also some hp just doing the bowls in the heads and back cutting the valves. This does not take a long time or cost alot. Knocking down the hump behind the exhaust is a royal pain. Don't remove it completly, just taper it. Be careful spending money on the stock heads though, because you will soon get to the point that it would be better to go aftermarket.