You could be one revolution off. Were BOTH valves closed on #1 AND 0 deg
on the wheel!

This is the simplest and most common problem people have when doing major
work like cams or rebuilding.

Here are some things to do.

Pull the driver's side valve cover off.

Turn the engine over by hand or have someone bump it until the harmonic
balancer timing mark is at 6 degrees before TDC.  With a new cam, don't
crank it more than you have to before break-in, so if your bumper is sloppy,
crank it by hand..

As you get close, watch the first rocker. If it is moving, then you are
timing for #6. If not, you are timing for #1.

At 6 degrees before, both intake and exhaust rockers (second and first
respectively) should be even and at rest. (You should be at the top of
compression, and both valves would have been closed for the upward stroke.)
They may even wiggle if you grab them.

Put the valve cover back on.

Put your distributor in now, with the cap off.  The rotor should point to
where the #1 spark plug wire will be in the cap.  Put the cap back on.

Put a test light on the negative (-) side of the coil. Turn on the ignition
(don't crank).

Turn the distributor very slowly counter clockwise. When the light goes out,
stop.  You may have to back up and try a few times to get just the right
spot where it goes out.

OPTION: Instead of the test light, you can hook a timing light to #1 spark
plug wire and watch for the light to flash.  Remember, as soon as it flashes
in the counter clockwise turn, stop.

Lightly snug the hold down clamp.

Put the timing light on #1 if you haven't already.

Pour a couple of ounces of gas down the carb.  I'm assuming the carb is full
since you have already been cranking it.  Otherwise, pour some gas down the
vent tube to fill the bowl.

Start the car.  Better to have someone crank it and you work the gas.  Keep
your face away from the carb.

Check the timing and set the distributor. Tighten hold down clamp.

With a new cam, you need to run about 1500-2000 rpm for 20-30 minutes as
soon as it starts, depending on what your cam manufacturer suggestions for
break-in.  You should watch oil pressure and water temperature, and unless
pressure is very low (for example, running 20 when normally 30) or water
temperature high (running 200-220 when normally 180), keep running for the
full break-in time unless you hear parts breaking or severe fluids leaking
(oil pouring out somewhere, water running everywhere.

I have set the hydraulic lifters during this time if you don't have them set
already.

After you have done the break-in, drain the oil and pull the oil filter off.
Cut it open to check for metal in the filter. You may see some, but if there
is a lot, you might have a problem.

If no problems, leaks, metal, overheating, and so on, put in fresh oil and a
new filter and go have fun.

Good luck.  Hopefully, I didn't leave anything out.