About 35 years ago my brother had a 402 that did that after a hydraulic cam swap. Not sure what the duration was but lumpy for sure and somewhere about .600 for lift.
He was told the GM High Performance springs would work... It ran for about 20 minutes and it finally would not run any more. Those lifters look good compared to his. Springs were checked post mortem and the closed pressure was good but the open pressure was in solid roller territory.
