I have not had a problem breaking in cams with a 340 type single spring with a dampener. It would have to be a pretty stiff spring to cause and issue. The dampner itself doesn't add anything to the seat pressure.
If I were in your shoes, I would tear down your engine clean everything and put it back together with new bearings if needed. I would then get another hydraulic flat tappet cam (not comp), and find a set of NOS or NORS 30 or 40 year old made in USA flat tappet lifters to use. There are usually some listed on ebay. IIRC there is also a guy on forbbodiesonly selling a big block set now.
You are looking at $1500 bucks at least to convert to a roller cam set up. Not budget friendly to say the least.
