I've read somewhere that Olds Heads with the stock springs can only go to a max of .500 lift.

I'm mapping out my next project and I was looking at a cam that is .496/.520. Mostly likely going to do roller rockers but not right away if I can avoid it, but if I have to...

I'm looking at the Edlebrock kit on Jegs. It has the 7111 Manifold, 7112 Cam, matching Carb, and lifters. Of course I need to get different push rods, but what about springs?

 

About half a dozen (if not more) companies grind this cam- 224/234 @ .050.
I recommend that you get some better springs, no matter how many of the cheap people got away with it.
This cam needs some compression (more than 8.5:1) and some springs that will not go into float before 5000 rpm. The stockers will be lucky to have 80# of seat force, and this cam really needs more than that.
Even IF they clear the lift.
Will they clear can only be answered by looking at your particular cylinder heads. If there has been any work done-all bets are off.
Have them looked at...please.
A 3 angle valve job and a set of springs is better money spent than the rockers at this level.
JMHO
Jim