Go one cam size bigger,xe 270,after all it is a 400 , and its sounds like you should have a tire fryin motor!!!With the right tires and gears I think its goin to feel like the front left tire is coming off the ground when you get on it!!Your lookin at about 1100 to 1200 bucks for the heads,intake ,cam lifters and springs.These are new retail prices,used heads and intake will lower this alot!!