I spoke with Joe as well as the guys from Cobra Automotive. Both think it’s likely a top end issue, perhaps a push rod. I fired it up again and about every 2-3 seconds it makes a pretty loud clank noise, seems like near the manifold. I’m hoping a push rod slipped off the rocker arm, or a rocker arm broke. Cobra Automotive are picking up the car in 2 weeks to bring to their shop and have a look. I rechecked the
oil and it’s nice and clean and no leaks anywhere. Hope it’s a top end issue, if so, wonder if a roller setup would be nice while there?
Sounded like this, first 5 seconds of this video:
https://m.youtube.com/watch?v=kOLZ9io8cYc