very rich 86 325

I’m working on a 1986 325 six cylinder. The timing belt broke and bent the valves. The head was changed and has never run right since it was done. This all was done before I started working on it. I fixed a few little things like the air in take tube and a couple of vacuum lines. It started up a lot better but stop running after about five minutes. Could not get it to start up again. Found the cat was glowing orange. It seems to be running very rich. The plugs are black, the intake is wet, and the cat is glowing. Is there a way to check the trouble codes without a scan tool? What might be causing it to run so rich?

Thanks