Engine wont start

Has all 3-amigos-Now its time to check if the valve and ignition timing is correct

There are a few things to get cheched that might be an issue;

The fuel pressure with and without the vacuum line that changes the pressure with RPM increase. It should be different between the two and if not, the fuel pressure regulator may be bad.
I am providing you with the genral test procedure and diagrams which show the location of the test port. Most Advance Auto or Auto Zone stores have these on a loner program that you can borrow.
Check the ait intake tract for obstructions.
Check the exhaust and catalytic converter for obstructions.

There is a genral procedure in a no start situation to follow and follows a process of elimination in order of most likely to least likely sources for the problem.

I am giving you the link for a walk through tutaorial of diagnosing a no start vehicle and how to fix it.

Here is the link;
https://www.2carpros.com/articles/car-cranks-but-wont-start

If you need any further help let me know and I will respond ASAP.

Woh! Did it snap between lobes or at the drive end where the belt is? That will definately keep it from starting. You might want to pull the pan off after your pour a ton of cheap oil and/ or some engine flush. I never was a fan of engine flush in high mileage motors or using it in a running motor. If it is used in a running motr a higher than reccomended viscosity oil should be used. So, just think about flushing out some of the tiny metal particles that dang cam might have put into the motor. I am a perfectionist so I overdo things so don't let my suggestion or comments freak you out. The oil probably barely pumped through the circuit and if there is any metal, it will fall into the pan and settle into the sludge that is in all pans it tends to get trappped there and that is why I reccomended removing the pan after pouring oil through so you could wipe out this sludge. You certainkly have 90% off any metal cast off by the cam laying in the head. It is a good thing it never started and really pumped stuff around and possibly thrown the broken cam through something and damaged it. Including you. So, it actually turned out well that you caught it and it failed nefore it ran, that would have been much worse.
You can pour some cheap oil through and/or wipe out the cylinders if you want to over do it like I tend to do.
I am very glad you caught the problem, good eye by the way and your thanks means a lot as not everyone says that.
Is till can't believe it snapped on you, very unusual. You will certainly get a head from the place you got the damaged one that they consider top shelf or built from a low mileage core.
If you need anything else when you are getting it back together we are here and glad to help.

Take care

Dr. C

PS I just caught that it was the second head. Unreal. I would freak. If you use the search window on the site, it will help you find reputable head rebuilders near you. It will work if you search for anything about heads or re-manufactured heads. It knows where you are by referencing your IP address. All links in this site have stood the test of tiem and would not be here if they did not have a good performance record.

If you had the tranmission out and especially if the engine is a different block and/or the flywheel form another engine was used. Basically anything not used with the thransmission before, and did not replace the pilot bearing or do something to re-surface the flywheel and use a friction plate of pressure plate that it was not used with before that can cause problems. After time friction surfaces become worn into each other just like brakes. The cheapest way to re-surface, if the surface of the pressure plate or the flywheel is smooth and not grooved at all, is to break the glaze with a high grit wet/dry or emery paper. 1000 grit or higher, in a cross hatch pattern. This gives it a new surface to break into. It is not the best practice but some flywheels are not thick enoguh to re-surface and meant to be replaced and pressure plates are menat to be replaced.
The vibration and lack of power may be engine related. If you got another head from the same place, I think you said you were gettng a refund and were going somewhere else, it is possible you got another bad head with a wiped cam. This is when the cam lobes are so worn that they no longer can open the vavlves enoguh and cause the symptoms you have.
Before you worry about that, you should have the trouble codes pulled. Advance Auto and Auto Zone parts sotres will do this for free. If no trouble codes come up, you should test the fuel pressure. I gave you the instructions and diagrams necassary to do that a few posts ago. The parts store I just referred to also have the test gauge you will need on a loaner basis for free.
I think pulling the codes and the fuel pressure test is the best place to start as the vibration and lack of power sounds like it could be lack of fuel.