Vacuum leak?

[Zsomething]

So, I am up and driving with the round top carburetors on my '73. The car fires up perfectly after sitting for a couple of weeks when I was too busy to drive it.

But, I have a problem now with starting facing uphill. At first, I thought it was just me being rusty with the 5-speed.

Now, I think there is no torque at low rpm under load.

When I went out to a quiet hill to test it out, it would lurch forward with each engine rotation (sort of like it is only using one cylinder). If I hit the clutch fast enough (after a few rotations), the engine won't even die sometimes. On flat roads, it's perfect. On substantial hills, it's undrivable. and everything in between.

I just put new round top su's on. So, the 'smog stuff' is still present on the balance tube. But, none of it is attached yet. I have a mind to hook it back up when all is running well, because I don't particularly hate clean air. So, I have rubber vacuum boots (probably not fuel resistant) over the currently unused vacuum ports.

So, is there a good set of steps to go through, or a list of things to check for a vacuum leak? Is my problem something else entirely?

Edit: I started to try to spray carb cleaner near the places that might leak. But, the can that I had wasn't atomizing very well (at all). So, I'll grab another can tomorrow.

Thanks.