Those old Peaveys and Fenders were made with white (northern) ash. Not the same as swamp ash, which isn't a real species anyway. It's just a music marketing term that can cover more than one species. And a fairly recent one at that -- never saw the term used before the early 90s.
But swamp ash can be heavier than mahogany. It's just that you're much more likely to find a lightweight example of swamp ash than white ash.
Thanks for the pictures.
Swamp ash is another name for black ash and it is generally lighter than other types. I'm 33 and I can remember my dad(a woodworker) referring to it as "swamp ash" when I was a little kid. I was just saying that it seemed odd to me to make an already neck-heavy instrument even moreso by using wood that is usually lighter than mahogany for the body
and elongating the headstock.
Not trying to start an argument. God knows I'm no tree expert.