What is this and why would it be there?

I’m not smart enough for cam specs. I would figure out what stroke and cylinder head I was going to run. Then figure out my rear gear and about what the car weighs and call one of the recommended cam companies and tell them what you goal is and all the above info. I run a pretty max effort x head without eliminating the pushrod pinch. Which averages around 275-280 cfm at .555 lift. I am required to run a stock casting iron head. If I wasn’t I would buy the new aluminum trick flow head. If you want to run a stock cast iron head, you should understand that its not cheap or easy to get them ported to the level to support a stroker, plus they really can only support about 420-430 CI. If you want to go that route I would recommend Porter Racing Heads, Dwayne Porter is on here. There are just so many better head choices than a stock casting that unless you REALLY want that sleeper look or are required to run one it is pretty silly to spend the $ on them. I don’t like hydr lifters because they either collapse or pump up and cause grief. A solid does not require that much maintenance. Once it settles in, you can check it once/twice a year.