[James]

If you are only missing the tube, you can make your own. I use brake line for my tube, be sure to debur the ends after cutting it. I assume the engine is on the engine stand, I would add the engine oil to the engine (for your full level). Cut a tube longer than 18" (some of it needs to go into the block) and install it into the block. Place the dipstick into the tube and bottom it out on the tube. Pull it out and see where the oil level is. Then cut the tube until the oil level is on the full mark on the dipstick. Remove the tube and debur the tube ends. Reinstall the tube and recheck level.