First off, you will need to put the cam in the motor, the lifters in, the heads on the engine, and mount one rocker with a pushrod on the motor. Then, with a dial indicator, see how far the rod pushes the lifter plunger down with the lifter on the flat side of the cam. If it is between 20-60 thousandths, you are ok. Best to stick on the loose side of that, so 20-40 thousandths are better. If it pushes it down too far, then you will need to shim. If it doesn't push down enough, you've gotten the wrong size pushrods. I suspect Paul and Fred already know that you need 7.200 pushrods for that cam. That actually makes sense, because the 605 lift cam in my friend's car required 7.300 pushrods, and a slight shim under the lifter (15 thousandths).
Chris