Balancing of stroker kits and vibrations

The 360/408 in my Dart has always had a minor but irritating vibration or harmonic that has just bugged the **** out of me. I didn't build the engine so I'm not sure if it was internally balanced or not when assembled. Anyways I pulled it out a year ago and installed a Mopar magnum 360/390HP crate engine with the correct flex plate and the issue seems to be gone.

The stroker kit is an Eagle Street and Strip Rotating Assemblies 20502030. Anybody know what the bob weight is suppose to be on these cranks as delivered? I pulled the piston, rod, rings, and bearing and weighed them as an assembly. They weigh in at 1294 grams on my fairly nice digital postal scale carbon and all.

Crank has some drilled holes in the counter balance so maybe it was balanced. But other strokers I have put together with forged cranks needed mallory metal. This crank is cast and doesn't have any of that.

Anyways I'm going to have it check, just thinking out loud here mostly. Any thoughts from the techs.