Gloat e Boast são sinônimos?

Hello dear all,
This is my first time in here. I have been reading the emails and it has just been impossible to stop, due to the amazing and endless curiosities.

Anyway, I am going to be sitting the CAE next month, so this site will be so helpful to me. And I just hope to be able to help as well, as much as I can.

I am a bit fussy about all and any detail, so can you imagine how pick I am regarding the synonyms?

If I can exploit all my new friends from here, then there it is:

Can I replace the verb "gloat" by "boast", and vice-versa?

Thank you very much endeed, and I am looking forward to hearing from you.