Which Valve Springs with Purple Shaft P4102661?

I never ever run any lash that loose. Ever. Back then they used a long, slow lash ramp because springs were marginal and valves were super heavy.

You can lash them at .022 hot on both sides and be done with it. Anything else is way too loose.

Once you are confident you have the hot lash set correctly, you can let the engine get cold, and then measure the lash again.

Whatever it is cold is what it is and from that point forward you can lash the valves cold.

If you do it this way, you'll end up with a valve lash that is much more consistent. This is because when lashing them hot the engine is actually cooling off fairly quickly. If you are even fairly handy with a feeler gauge, you can test this.

When you cold check your lash you'll see the valves you lash last are the tightest, because they were the coldest when you got to them. The very first valves lashed will be looser cold.

Try it.