I installed the Hella twin horns this weekend. Many thanks to bbsilver for his extremely detailed instructions. I could have done this without them, but I'm sure I would have made more mistakes along the way. The only changes I made to bb's installation, was using ring terminals for grounds instead of just bare wire. I also put star washers on all ground and power connections. Just a little insurance for a good contact. I was even able to install the relay behind the drier bottle.

Once again, I am amazed at the value this board provides for this kind thing. I've spent many hours working on cars over the years without the benefit of other's work.

I do have to say though, that after spending about four hours on this install I had a feeling of . . "boy that's a lot of work to make my horn sound like a Cadillac".:

 

Supertones or their trumpet style? Do you have a photo you could post?

 

They are the Supertones. I don't have photos, but if you do a search on bbsilver's post, they are exactly the same. It's really a non-intrusive install. No holes to drill and minimal changes to original (cutting off original horn connector)