i agree with this, but one question before you deal with #4 its hydraulic or solid lift? if its solid then your gonna pretty much have that always. and you will have to adjust it all the time. if its hydraulic then ya. are you using a feeler gauge or by touch? basically set the cam to the flat side of the cylinder, take out all the play then give it an extra 1/2 turn.

 

When I had it rebuilt the cam was upgraded to a longer duration one but I am unsure of how to tell if its solid or hydraulic? Any tips on this one?

If it is a solid lift, then there's no way to adjust it?

What is it specifically that is causing brand new hardware to begin knocking?

 

really, listen to them. You valves are way out of adjustment and you are going to ruin that cam. Stop starting that engine till you read how to set valves and break the cam in.

 

Don't take this wrong, but you're in way over your head if you don't know how to tell hydraulic from solid lifters. Best that you get the car to a garage and have them adjust the lifters for you. Or get a knowledegeable buddy to come over and set them.
But for future reference; both are adjustable as they both use the same rocker arms to adjust. With the valve fully closed you can back the rocker off until it has a slight amount of play. Then take your thumb (or a wooden hammer handle) and push down on the pushrod end of the rocker. If it moves under spring pressure you have hydraulic lifters. If it doesn't move they are solid lifters.
If they are solids, then you need to know the specs to determine the valve lash, as it's different for different cams. Most need about .030"-.035" clearance running hot, but that can vary with makes and models of cam. With hydraulics it's zero lash plus 1/4-1/2 turn.
Please get some help before it's too late and you lose a new engine!