With just a bit of research, the .375 H&H with a 270 grain projectile at 2400 fps is ballisticlly identical to the .358 G&H with a 250 grain projectile at 2500 fps.

Not to take anything away from the .358 G&H, but I rather have a .35 Whelen and a .375 H&H.

For the record. I have a .35 Winchester, which is essentially a .35 Whelen flanged!