What is a good donor vehicle(s) for 72 Cuda horns?

Do you have anything of the old horns ??? {like the mounting brackets ?}...The high and low note prestolite horns themselves are pretty much standard pieces other than the date code...They were made through a broad range of years...Any mopar from the mid 60s to the mid 70s should have the same high/low horns...The attaching brackets vary depending on the model...The barracuda bracket is basically an "L" shaped piece...Here's a pic of some E-body horns someone posted in another thread....

I have one horn but don't know if it is high or low. Was wondering if any car from that era is the same.

So what is the best way to clean them up? Can you bead blast? Can you just stuff some rags in the opening and tape if off before you blast or is there a better way of doing it?

All I've ever done is stuff a rag up in there and blast...The RR horns with the open diaphram are a little tricky to do....