Cylinder Locations?

[Bobbys Big Red Rig]

Just bought a late 99 F350 with a 7.3L Powerstroke. Bought from a mechanic at work who had purchased and installed a set of injectors from a International parts dealer. Did not install a different #8 injector like is recommended to reduce noise. Engine had a fuel nock after install. After purchasing truck I purchased the recommended injector. He what out injectors but I think he changed #7. He changed the passenger side rear, I thought #8 was the driver side rear. Want to verify before swapping. Labor was free and I got to help and learn swapp will be the same. Just want to make sure we do the right one. Where is #8? What are the others.

7 8
5 6
3 4
1 2
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