Those tubes commonly got bent when an engine was set down on the wrong side...or fell over in some cases. Sometimes they get cracked when they get bent, but usually this doesn't happen unless somebody tries too hard to "fix" things. If you find you need to replace one of these tubes, here is a suggestion: The original oil dipstick tube is about .5 to .6mm larger in diameter than common copper plumbing tube (3/8")...or looked at another way about .025 to .030mm larger all around...which is .0012". If you apply solder to the bottom 2 inches of a piece of 3/8" copper pipe you may find it fits pretty well now.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end