You never mentioned you replaced the heads. I believe you said it ran good for 133k. If the heads you installed were surfaced your pushrods may be to long. Or who knows what condition the seats are in the heads.
I briefly mentioned it in post #5 but not in the OP. Not sure of the condition of the seats on the new heads but the old ones were sunken badly, one exhaust valve was almost 1/8" up into the head. I'm trying to find the conversation with the FABO member to find more details on them. How can I determine if the pushrods are too long?
@Scody21 leakdown test is a good idea, at least an audible one using my air compressor and air line/spark plug adapter.