Mine is a few cranks quicker.. 

Set the choke for a cold start, turn the key, crank the engine while pumping the gas and stop after 5 seconds. ( I "imagine" the fumes slowly traveling down the intake to the heads).  Turn the key, crank and give it a little gas and it fires off.   The sequence is no different if I crank it for 20 seconds.  Mine demands a pause and fires off at "round two"

The choke sets fine and OEM coil spring pulls it off perfect as it warms.

This is the best mine gets!   I've had the Quadrajet rebushed and plugs epoxied. A new fuel pump might have cut a second or two off the cranking.  It's been like this for 30 yrs so I'm at peace with it.

I'll try the two crank start.

Mine has only been like this for about ten years.

That is why I think it is the deletion of anti-evaporation additives in fuel.

Surprising followup:  My C3 has sat for 6.5 months.  I turned the key and it fired off on the 3-4 rotation of the engine!

Or, you could get one of these.🤡

But seriously Willis, I agree with those here who bitch about the fuel. It's a power-robbin' jet-pluggin' blend that's here to stay. I've got your same problem with the carburetor on my '80 Toyota 4x4. I am sentenced to carb rebuilds much too frequently, just in order to pass this state's smog test. The Rochester I had on before was prone to being "dry" after just a couple of days sitting. I now now where the fuel was going, thanks to responders above.

Good luck on the fix.

Steve