These are Sanderson BB-4 blockhuggers. On my 67 Stepside they tuck up between the frame rails so nothing is hanging down and they did not require much in terms of cutting to fit. On the passenger side I needed to put a small oval notch in the upper part of the frame rail but it was only 3/8 inches deep and 2 inches long. If this motor was anything other than a 572 that would not have been required but the heads are very far apart on this tall deck block. They also required relocating the oil filter which I did.