Just an update, my buddy ended up putting hellcat lifters in his 5.7, got rid of mds lifters because of the cost. He did have the heads surfaced and valve springs checked and had a few bad ones, so new valve springs were put in, also a hone and rings while it was out. He used a tuner to shut off the mds and put a tune on it, he said it runs a lot better and much smoother than before.