I thought the head and block on the OBS F150's were fully cast iron?

 

http://www.ford-trucks.com/specs/2000_f150_1.html

 

Nossir, iron block and aluminum heads.

 

When pulling plugs on aluminum heads, you need to follow two rules:

1. Thou shalt not pull plugs with a hot/warm engine.

The engine should be stone-cold because hot aluminum-heads + hot steel-plugs = stripped threads)

2. Thou shalt not put in plugs without first applying copper anti-seize lubricant to the spark-plugs' threads.

This helps avoid stripped threads as well and reduces the chance of suffering later on if you violate rule #1.

 

NOT necessary if you use Motorcraft plugs, the threads are nickel-plated. You MAY use it in the V-6, but do NOT use it in the 4 thread V-8 heads.

 

I recommend that, if you do feel the need to use anti-seize, use aluminum-base rather than copper! Copper in aluminum can cause problems. Actually, though, with nickle-plated threads, you don't need to use anti-seize at all.

 

If you use antiseize, use NICKEL antiseize.