Need a quick what’s it worth WIW - 340 motor mounts
The mounts you have pictured are not a pair for a 340 A-body. Better identify them correctly or you will giving someone their money back. I am not going to tell you what they fit or worth because you will really get aggravated.
You bought something that won't work for you. Don't try and scam someone on here . I just made you aware you don't know what you have. Seams to me your looking for a offer on this site.
Put them on craigs list and take what ever you get that is close to what you paid. There are times you just have to take it on the chin when you make a mistake.