magnum 360 into a 74 duster that had a slant 6

I won't "disagree", because as you say; never say never... That said, in my limited experience with 5.9 Magnums I have found the opposite:'95 or '96 and newer (I've had a '97, '99 and 2000- OBD2 era) have had weighted plates and neutral convertors; but have been told the early OBD1s had a non-weighted plate and weighted convertor (no personal experience with early Mags)... so I guess the moral of the story is: ALWAYS check what you actually have- assume nothing! Just use the right convertor to match your flexplate, and vice-versa.
PS: 5.2 Magnums *ALL years* use non-weighted flexplates and neutral convertors- just to keep everyone on their toes.

Actually, you are 100% right. My statement above is wrong, I had it totally backwards. My experience is 1994 and older has the weight on the converter, 1995 and newer has the weight on the flex plate. I was confused because my motor is a 94, and I bought a weighted flex plate. But I only bought the weighted flex plate because it's the easiest way to balance it all out with my neutral balance converter.
That's what I get for posting at 4 in the morning after a bunch of beers.