Dipstick troubles - I have the same engine and I know your pain. Obtain from your local hardware store a very narrow steel cutting blade similar to use on the hand held electric jigsaw. Make sure to get the metal cutting version. They come in a variety of widths and lengths. Keep in mind that the dipstick tube is soft sheet metal and the block is cast iron.
Next, take a vise grip and clamp the saw at a 90 degree angle with the vise grip. From underneath or from the side, whereever you can, saw through the open hole and make two cuts just through the sheet metal. You will feel the difference in the cutting when you have gone from steel to cast iron. Take a small 8 inch 90 degree pick with a handle and with the side of a small ballpeen hammer drive the pick about 1/8 of an inch away from the cut between the cast iron and the sheetmetal. The broken dipstrick tube should roll up and come away from the cast iron. If it refuses, use a small penciltip butane torch and gently warm the cast iron. This will break out the rust and expand the cast iron. Once a space has been opened, remove the pick, use a pair of 90 degree angled needle nose pliers, insert one tang into the open space using the side of your ballpeen hammer, drive it is securely, then clamp the pliers and rotate it any way that you can. You will see that portion of the tube that has become clear separate and then pull out in one or two pieces. Good luck.
Inco Mec. Serv.