ok, why are 360 flywheels so expensive

Extremely important point! Attaching hardware. ARP bolts torque down to spec BY YOU. every time I hear stories about a flywheel breaking news is when someone wasn't watching their bolts and trying to change flywheels in between drag races or something like that.

Oh crap! I forgot the internet! I have to clarify myself of course it could happen 300 different ways but this is just the way I have heard of it happening...

Why so expensive?

It's simple manufacturing economics: Chrysler made one 360 flywheel for every several dozen neutral balance wheels.

Add in the extra cost and machine time to make one.

There are many alternatives and as stated, don't skimp on flywheels OR their attaching hardware.

The blue print is readily available, ANY decent fly wheel shop can match the neutral balance wheels to the print.