Any non electric 4 speed autos for a 360 mag out there?

If it came out with those gears on it then;IDK what caused that. Those spider gear teeth look almost new.
I've seen a lotta rearend carnage since 1972 but I haven't ever seen that combination.Put a SureGrip in it and that will never happen again
What's a JY?
The smallest rearend that will live behind a 408 is a Mopar 8.75, and it should be a clutch-type 4-spider Trac-Loc . Unless..... of course......... you got skinny tires. But I don't see the point of 408 plus skinny tires. That's just a recipe for disaster. And a big old embarrassment when a big-tired 360 throws dirt on your hood. If you peg-leg your rear, it won't be long before the crosspin retaining pin gives up the ghost and the pin launches somewhere; hopefully not into the gas tank, cuz it might be super hot. Remember when peg-legging, the spinning axle is doing double what the speedO says! And the oil temp is rapidly rising, cuz there just ain't a lot of it in there.And if you happen to be going around a corner some of it may not even be in the sump.
Sideways is the whole point of a 408 isn't it? Just remember skinny tires don't brake when going sideways. They just slide and slide and slide 'til you hit something.