I need to replace the glow plugs on my 84 6.9L IDI and was wondering what brands I should look for or if these: http://www.accuratediesel.com/shop/1.html are good for my truck or just junk glow plugs

 

Motorcraft/ beru. Most o th er brands are known to problems. Rock auto should have them at a good price.

 

i would steer clear of them. as said, rock auto has the proper ZD-1 glow plugs for your truck for $9.43 each
diesel filters.com has them for $8.55 each
[ZD1A] - Ford 6.9 Liter Diesel Motorcraft Glow Plug(E5TZ-12A342-B)

 

I ordered 8 glow plugs last Monday from Rock Auto, got them Wednesday afternoon.

 

Google "rock auto discount code". Copy and paste the code where it says "where did you hear about us" during checkout. Good for 5%.

 

These are Wellman/DieselRX glow plugs.
Some people have had issues; I've used them myself without issue.

If the price is close, you probably want to go with the Motorcraft ones, though, as they are considered the "best".