360 Tune Up

Waitaminite I got an idea
What does it do when cruising in direct? at same speeds as before in od.
And what are the secondaries doing?

Here's where I'm going;
What if
in od, at cruising speed, the 360 is so underpowered that you are deep enough into the throttle that the secondaries are opening? I mean you said the temps start creeping up at 70ish right. I know any 360 should pull that with 3.55s relatively easily in direct gear. But what about yours in .79od? If your secondaries are not opening, it's gonna take more throttle in od than in direct to cruise at the same speed. In direct, at 60mph the carb should still be on the transfers, with a very small throttle opening. By 70 the mains may be contributing, it depends on your cylinder pressure and fuelling.
But in od the throttle may have to be opened more to get enough power to cruise with. So maybe the mains are flowing. This would simultaneously point to both the lack of fuel economy and the engine is working harder to maintain 70. Just thinking. Now throw in the possibility of the secondaries being cracked, and that would be another can of worms.
What if is all I'm saying.