1969 E-950 Firetruck Bogging at high RPM

:banghead: My firetruck, 564 Cubic Inch V-8, Manual Transmission, loses power and backfires at higher RPM. Any suggestions for remedying the situation?

Check the timing and make sure it is advancing. Check the fuel pressure and volume. You might be running out of fuel.

Thanks friend, I will give it a shot

Check your ignition wires. A good time to do it is at night. If they are bad you will see them arcing to ground. A fuel starvation will not make it back fire. If it is old enough (pre-75) the condenser on the ignition may be bad.

Thank you all for your suggestions.

My first impression is that the timing chain is very loose or even jumped a tooth.