I have a 1978 Thunderbird that wants to start but it won't. Is it the fuel pump?

Spray a little starter fluid in the breather as someone is trying to start it. If it starts for a second or two then goes dead it will be fuel related issue causing it not to start.

Make sure you have spark also. You don't say if the car has been sitting or in storage for some time or not. Is the fuel fresh? When was the last time you drove it? More info would be a big help.

It could also be old gas that has turned to varnish. I have a '77 T-bird that sat for many years and I had to siphon out the "gas" which was completely disgusting before it would finally turn over.

Have you tried any of the suggestions above yet??? Bring us up to date and some more clues.

I've driving it. It has new gas

If you're driving it now does that mean the problem is solved? If so, what did you find wrong with it?