Can anyone tell me if this springs on an 84 chevy 4 bolt, 76cc heads are factory. Looks like spring with spring inside. Supposely the motor has a mild thumpr cam, seems just above stock. Also the top of these springs has 2 different tops? Any idea what and why this may be?

 

The flat spring inside is a damper, if the outer spring breaks the damper keeps the retainer from coming off. Those are valve rotators on top.

 

Almost looks like a thick spacer to make up for weak springs

 

They rotate the valve, not good for performance. You don't want extra weight on the valve side of the rocker stud in a performance engine. The spring height is shorter with the rotators. Are the rotators only on the exhaust valves?

 

I really didnt pay attention to that, i will pull the covers back off and see

 

Yes, they are rotators for rotating the exhaust valve from overheating preventing hot spots and later in life, 'burning' the valve getting a hole.
As suggested, the inner spring is a dampener dampening spring harmonics reducing fatigue shortening the spring life.

 

Hanks for all the info on this.