coil without ballst resistor?

That's it I don't know. I doubt, unless someone has tested a number of coils that anyone really does. There never was an "old look" coil that was designed "for" the GM HEI There was a reason the older Mallory and Accel coils were huge---to put up with the large amounts of power fed to them. More modern coil design allows somewhat smaller.

the other thing is "you might be over thinking." How much HP does this engine produce, what fuel and compression, and what makes you think you need something "this special." As I pointed out earlier, a stock Mopar coil driven by a GM module, no ballast, puts out considerably more spark than the Mopar ECU. It "just might be" that most any cylindrical PERFORMANCE coil will "do ya" in good shape.