I just did a cam swap on my 318, and I'm getting no love on start up. It barely runs for 3 seconds at a time. It actually behaves like the one time long ago my timing chain slipped on me, so my hunch is that the cam is out of synch. Facts to know:
I installed the timing gear dot to dot. Standard key, no offset. I did not degree the cam. Cyl #1 at TDC. I realize that this will be TDC ignition stroke for #6. (Correct?) Timing gear and chain had about 3,000 miles, so basically new.
I used a torque wrench throughout. With the build complete, I hand-rotated the crank once or twice to make sure everything spun, no problems detected.
On fireup, I made sure the rotor was at #6 while crank was at TDC. I got some putter-putter, but no real firing, played with a few timing settings, no love. So I second guessed myself and reset the distributor 180 off. This time there was immediate fire, yes, outside the carb, so I knew I had it right the first time.
I reset the distributor back to normal, and this time I got a little bit of firing...super low rpms, but it just wouldn't open up, even though I swept the dizzy through its entire range. Next, I reasoned my way through a reset of the intermediate shaft, thinking that I could sweep the dizzy through a different range of degrees, if you follow. (I'll add as an aside that it seems curious that we never talk about correctly referencing the slot for the distributor as part of an initial setup, maybe I'm thinking too hard).
Carb and ignition worked fine before, newer Holley 600 is confirmed to be flowing.
I have no reason to believe the stock balancer has rotated. Timing was fine on my last build of this same motor a few years ago.
I've done this job twice with success, I'm no expert but I'm a bit baffled as to where I went wrong.
Any thoughts appriciated.

TDC compression stroke on number one cylinder with the marks lined up and see where the rotor is pointing.

Well the marks are all buttoned up now.
But during the build, I knew that with dot to dot, the rotor should be at #6, and that's where it lined up to when dropped the distributor in. Seemed normal.

That's not what I said. Pull number one plug. Bump it over until on compression. Rotate to line up line on balancer to 0 on tab. Then see where the rotor is pointing.

How long did you crank the engine over... are you sure the lifters were pumped up

Gotcha! I mistook timing marks for cam dots in your comment, understood.

Mr P, no I'm not sure. I ran my drill to the oil pump but something seemed a little off, maybe I did not engage the pump and my pre-oil procudure failed. I did pump up the lifters when I installed them, but that was two months ago. So maybe I'm just not getting strong enough valve action. I had several 10 sec cranks.

I may be misinformed but I thought the current recommendation was not to pump up hydralic lifters before installing so as not to hang some valves open before they can bleed down to proper capacity. I've installed many sets without pumping them up. Start with a compression check on a couple of cylinders after verifying your pre-lube technique. Bill

Is this a brand new, flat tappet cam? How long have you been trying to start it? The break-in lube is probably gone at this point and firing it now would wipe the cam on break-in. Motor needs to fire almost immediately when breaking in a new flat tappet.

Make a piston stop out of a old spark plug by knocking out the center electrode and porcelain insulator and use a long enough 1/4 bolt to hit the piston top around 20 to 30 degrees before and after TDC to make sure the dampener has not spun the outer ring with the TDC timing line on it
I had a old 318 truck poly motor car hauler backfire in the driveway when cold making the timing change jump one tooth, it was real lazy and I couldn't make it run properly until I replace that timing set
Good luck
Let us know what you find out about what went wrong

Yes Mark, flat tappet. This is one of my worries, that I've already wiped the lube and need to break it down and re-apply. Proably 60 seconds of combined cranking.
As for the recent pump-up-or-not-pump-up thread, yes I recall more of a consensus to NOT pump them. This came to light, to me anyway, an hour after I pumped them! Assuming that my lifters have been under pressure for a few hours now, maybe I can bump the starter to put a load on a few more lifters, and they will unpump a bit overnight. Comp check is a good call too, thanks!

Some cam and crank gear markings can be misleading. Without seeing what you put in there it would be hard to say that is the problem. Degreeing it would rule out that problem. I ran into a problem years ago so I do not trust the dots.

i wonder if the intermediate gear slot is not in the correct orientation and the distributor can't provide enough timing?

Yes, I wonder this too about the intermediate shaft. It makes me wonder why I've never seen this subject come up. I did reset it once during my session today. I'm guessing the intial set up of the shaft should be such that the slot is in line with the #1 and #6 terminals.

The orientation of the intermediate shaft means nothing.

As long as at TDC on #1 cylinder the rotor lines up with #1 wire you are good.
The reason the service manuals show the orientation is so that by following the procedure the average person will be able to have enough distributor movement without the vacuum advance unit crashing in to anything.

The procedure came from the engine test stand assembly procedure when the engine was tested at Chrysler.
Follow what Nitrousin said . Get TDC on #1, with both valves closed, and check the rotor location.

I doubt your lifters are the issue after all the attempts to start the engine.

the slot doesn't matter IF you don't care about plug wire location on the cap. if the plug wire location on the cap is correct then the slot needs to be correct to allow for proper distributor movement. some people don't care; i do.

Thanks y'all, all advice sounds good. Hope to get at it later today.

Go back and start the whole valve and ignition procedure again... if you need help just ask

If you really think your cam is installed wrong, take off the valve cover rotate engine and watch the intake and exhaust valves. When rotating the exhaust valve will open then start to close, keep rotating slowly and the intake will begin to open, when the balancer gets to zero this is the overlap period, basically both valves should be open and by the same amount. Exhaust closing and intake opening. If one is open a lot more than the other your cam is out of phase. If you use a dial indicator you can check for advance and retard, if the cam is open a few thousands more on the intake it is advanced, the exhaust open more it is retarded. If you are at least a tooth off, you should be able to see the difference with your eye. And when setting your distributor, remember your coil does not fire at zero TDC it fires 10 to 20 degrees before TDC.

Ideally yes but I've had two instances where we spun the motor over for a heck of a lot.longer than OPs stated 60 seconds and both motors were fine. One is videoed on my YouTube channel where we were trying to do break in in cold weather. Both times the cam was fine and the car went on to make 100s of 1/4 mile hits without issue. I've had guys tell me "if it don't start on the third spin take the cam out it's junk". Doubtful.