Please help with ticking noise

Well, I'm in kind of the same situation, 383 with ticking niose but only when the engine is cold.
Got the ticking noise when I bought the car, totaly stock 383, I then changed the 516 heads to a reworked 915 heads, new Lunati cam kit with lifters (701/301LK if it matters) new pushrods to get the right preload, new cam drive kit from Summit and so on...
Now when I start the engine cold I get a ticking noise that almost disappear when the engine get hot/warm, just like before I changed the cam etc.
I run 20/50 oil and here in Sweden the temperature is about 60-70F, should I use a thinner oil, maybe 10/30?
I've isolated the tick to cylinder 1-3 and I can hear it slightly even when the engine is hot but not as much as when the engine is cold.

Any thoughts?