Ever Seen This Before?

That 'aint stock, I can tell you that much.

The right way to is to have the correct balancer for a 360 and and an aftermarket flexplate to allow for a nuetrally balanced converter. Both the flexplate and balancer should be brought in along with the crank, pistons, rods, etc. when having the assembly balanced. This way, you can swap converters in the future without having to worry about balancing.