Can I run my motor with the dipstick tube in the block?

I recently changed my headers to shorties in my 5.0L and the dipstick tube is loose. I went to check my oil and it popped out. Now what should I do? Should I just cap it or try to take another 30 mins to put it back in. The headers are preventing me to have a good fit. Is it going to be catastrophic if I just leave it be without anything in the hole?