340 Motor with 360 heads?

The set of J heads I have say 360 on them. They are on 70 340 motor. Like what was said before the 360 cast in them doesn't mean that is the engine size. The pictures you of the "balancer" isn't the balancer. That is a picture of one of the crank throws and holes you refering to is how the factory balanced the crank. Yes an aftermarket intake has been added to increase the performance of the engine. My j heads have 2.02 intakes and the exhaust seats were not the hardend ones. I know because they were replaced with hardend seats and all new exhaust valves.