The crush tube is an important part of the conversion. Adding extra strength to the crossmember mounting points.
As you can see in the pic,the original points are not that robust.Locate the existing hole in the chassis rail & insert a pointed punch in the center of the hole. Align the punch as accurately as possible and hit with hammer to mark the rail.
Correct tools make the job go easy. Get your self a multi stepcutter as shown. You will have much use for this tool as your project progresses. They make life easy. Make sure the mark punched from underneath is centered in the chassis rail. Remark with center punch and cut the correct size hole for the crush tube to fit neatly in the hole.
After cutting the crush tube holes smooth off the hole edge with a file or sander. Make sure to vacuum or blow off with air the swarf residue including inside the chassis rails. Rust proof cuts & inside chassis rails. Dont scimp here!
Correct position for crush tube when installed. Tubes are supplied to correct length but due to variations it pays to check the depth. Tube should have approx 0.5mm (0.020") crush. File end of tube if required for correct fit.