Colin, a lot of care. They are easy to put into the cam followers as you can see what you are doing, put a blob of grease on both ends. Make sure the two rods are at the same height eg at the lowest part of the stroke and are parellel to each other. Now slowly lift the rocker box over them with your thumbs pushing the rocker arms to the top. Then gently lower the box onto the greased pushrod cups keeping pressure on the rocker arms. Drop in head bolts and tighten, sorted for one box. Ditto for the other, adjust clearances as per handbook.
