I have a 1992 f-350 runs very good but recently its having problems starting. Its starts right away with starting fluid I took off the front two glow plugs and there are torched. Is there a reason why it would burn the glow plugs like that? I had replaced about five glow plugs in January and it worked fine until now. I would really like to know if there is anything else that can burn the glow plugs or maybe I have to install a specific make of glow plugs. The ones I replaced are from autozone.

Personally, I would stick with Motorcraft glow plugs. If you shop online, the prices are not too bad. Ohm test your glow plugs, as described below. This link below should give you some good ideas:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-8.html#post1415281

Starting fluid is likely torching the glow plugs, especially if you've done it more than a few times.