Were you thinking of having the oil pan off when you are putting it in? They must be bent and put in position so not to hit the crank.. Many guys instead of using stock type tubes , make there own. They get a fitting that is 1/4" pipe to 3/8" tubing. Then after taking out the old tube , tap the hole with a 1/4" pipe tap. now just get a piece of 3/8 " steel tubing and cut and position to fit .. This is what I did after not getting a new tube to fit and damaged it .
You must take the oil pan off to do a dip stick tube replacement. There are aftermarket chrome tubes and dip sticks available at stores like NAPA. I bought one for my 368 rebuild. It was a universal tube & stick with enough overhang into the pan to enable a 3/8" tubing bender to be slipped onto it to bend it enough to clear the crank journal which it would interfere with if it were left unbent. The aftermarket tube has a slightly thicker wall than the stock GM tube and is more resistant to being broken off at the oil pan rail which is what usually kills them. I have a new GM factory tube also but I decided to go with the aftermarket tube because of the thicker wall and the chrome appearance (old saying, "If it don't go.........chrome it").
The instructions on the factory tube packaging say that it must be staked to the pan rail to prevent its turning. Nonsense. The tube is so tight in its hole or so tightly captured by the exhaust manifold that staking the pan rail to prevent its turning is redundant. I don't know if headers would capture the tube and prevent its turning but that's a decision that can be made on the fly.