What will cause my float bowls to go dry

I would check bowl gaskets for a wrong gasket installed.
Many times, a bowl is said to have gone dry, when if fact, it has not. The liquid level is just too low to be pushed up and over the tops of the wells without a properly functioning choke. The accelerator pump by itself, cannot always meet the demand of starting a cold engine without a choke.

With a properly functioning choke, engine vacuum moves up from underneath the throttle valves to underneath the choke plate. This causes every fuel circuit during cranking to spew fuel in copious amounts. Most of it will be liquid, and will quickly attach itself to the cold engine parts. It will sit there until the engine fires up. As soon as it does, the PV will shut off, the choke will be "pulled off", the vacuum restored to under the throttles, and the low-speed systems take over. But some of that fuel during cranking, will be atomized small enough to be carried along in the airstream, eventually reaching the chambers, and combustion can commence.
When it does, the now-running engine will begin to pull fluid off the cold surfaces where it has just been laying until now.
The choke has been pulled off, the fast idle has been set, and now begins the warm up.

But if you don't have a working choke,
and you are running a ton of Idle-advance,
then your transfers are nearly shut off, and the Mixture screws do not have the capacity to feed the cold engine during warm up, much less start it up. So there you sit, frustrated as hell, thinking the bowls are dry, and pumping the pedal..

BTW
you guys south of the border must have different gas than we do.
My HO 367 has no problem starting and running on 87E10; even down to to the freezing point of water, without a choke.
You know, 87 is NOT corrupted with anti-knock chemicals that slow combustion down .... right, lol. The modest 10% alcohol content is easily compensated for, in the tune. I've been running thatchit since 1999, and the car has gone 93 in the Eighth with thatchit, at 3457 pounds/me in it. Thatchit is without question, Baaaad, lol.
Yes, I agree that it evaporates rather quickly in an open container. No big deal to me, since I don't live in a really hot climate. Parked in my carport on the shady side of the house, it takes two weeks before I have to pour a lil fresh stuff down the airhorn. Click-vroom, and away we go.