W2 rocker arms.
The ones on the left are an older model without the holes drilled on the top. They also sometimes had the hole at the back by the pushrod cup wended so the oil was forced down the threads into the cup. See pictures below. These were from Direct Connection in the late 1980's. First set I ran.
They changed the casting to the ones on the right in your picture when they began making both the econo W2 without bushing (cheaper rocker arm to buy) and the bushed W2 for higher RPM use (see my earlier post with the different part numbers. For the higher RPM bushed they added the bushing, it blocked the top oiling hole and they added the valve stem oiling hole under the nose.
Regardless of which ones you run they will work the same and there should be no issue to interchange them.
The ones on the left are an older model without the holes drilled on the top. They also sometimes had the hole at the back by the pushrod cup wended so the oil was forced down the threads into the cup. See pictures below. These were from Direct Connection in the late 1980's. First set I ran.
They changed the casting to the ones on the right in your picture when they began making both the econo W2 without bushing (cheaper rocker arm to buy) and the bushed W2 for higher RPM use (see my earlier post with the different part numbers. For the higher RPM bushed they added the bushing, it blocked the top oiling hole and they added the valve stem oiling hole under the nose.
Regardless of which ones you run they will work the same and there should be no issue to interchange them.
