I will try to be as succinct as possible.
I rebuilt the head out of a '80 Courier and installed in our 1979 Mustang. This is the first time i had ever done anything this complicated. Given that, I was thrilled to see the engine crank and turn over when we turn the key.
But no start.
The car ran fine when the head seized up and broke the timing belt.
We have put fresh gas in the tank and have confirmed that fuel is moving to the carb.
I have double check the firing order.
I cleaned the carb as best I could when I had the top end off the engine.
New spark plugs.
Here is a video. it shows a back fire out the carb.
That is all the information I can think of now. Any and all input is appreciated. Please let me know if I have left any helpful information out.