Toronado.org

i have been told i could swap a 76 Eldorado rear axle but i have found one and it has coils instead of leafs...any advice would be helpful

I can't answer specifically to the leaf vs coil spring issue; I am just starting to look into this myself as I work towards my own 4 wheel disc conversion.
Here are some articles that may help

The hydro-motive site is long gone, but has been archived here:
https://web.archive.org/web/20080807132725/http://www.hydro-motive.com/toronado/
It has the original Diskenstein article which covers 4 wheel disc conversion. Sadly, many of the photos are gone. I believe there is a complete copy (with photos) somewhere on the TOA website, but was not able to find it.

A well documented article on front drum to disc conversion.
http://www.breznick.com/toronado/brakes/
The author believes it's not necessary to do a 4 wheel conversion, but personally, I want to because I plan on putting modern wheels & tires on mine. and don't know how you'd have discs on the front, drums in the rear and have wheels to match. Each pair of wheels would have radically different offsets.

Certainly front discs are a huge improvement over drums. I've had 3 79 Toro or Eldo cars, driven many miles over 30 years. My experience with the first Toro and all my RWD cars is that front disc/rear drums are fine if you're not into racing. The last 2 FWD cars with rear discs were quite troublesome due to the
the emergency brake arrangement, the last one wasn't even safe until I added a rear proportioning valve. I am not a fan of rear discs. Bruce Roe