My '71 340 with the 305/.525 Comp cam with matching lifters/springs ran fine prior to my indexing my new bellhousing this weekend. Granted, I did have to "feel" my way around that process as it was my first time doing it, so the engine spent quite a few revolutions being turned by hand. Once I had the car all buttoned back up today (the car sat 2 weeks during this time as well) upon firing it up, the lifters wont pump up and are making some very loud clatter. I only let the engine idle for 20 seconds the first time and then another try I let it run at 1500 rpms for about 60 seconds and still the clatter continues, Loudly.

How long do I need to let it run before the lifters start to pump up again? I really don't want to hurt this engine as I have less than a year's run time.

THANKS!!