The outer most ports (front and rear) on the Magnum are smaller on the lower outside edge then the LA 340/360 ports. But TTI took it upon itself to make the headers fit the Magnum ports so on the LA heads they "hang" into the port with some partial blockage. But since its the lower edge not as critical. But I hate the fact the TTIs don't match my LA ports. For the cost of TTIs there should be a magnum version and an LA version.