Any Tips for Spark Plugs that Won't Budge

Trying to change my plugs. Have autolite 45's. They are no more than a year old. New block, so it's the first time it's been changed. I couldn't budge any of them. Tried 6 or them & no go. I don't want to force it & break the head, so I have stopped. Any tips on what I should do? Is it safe to spray some type of wd40 or similiar on the threads & try to let it penetrate? I would hate to bring it in to shop just to change the plugs, but I don't want to risk breaking any of them. Can't figure out why they are so tight or how they got so tight. Heat?
 
Aluminun or cast iron heads? If they are cast iron then spray a little WD-40 or other penetrant and get a longer cheater bar, the plugs might break but the heads will be fine. If they are aluminum then spray them and try again but very carefully. If you did not use antisieze on the plugs in an aluminum head you will might be removing the heads and taking them to the machine shop to have steel spark plug seats installed.
 
Ronstang said:
Aluminun or cast iron heads? If they are cast iron then spray a little WD-40 or other penetrant and get a longer cheater bar, the plugs might break but the heads will be fine. If they are aluminum then spray them and try again but very carefully. If you did not use antisieze on the plugs in an aluminum head you will might be removing the heads and taking them to the machine shop to have steel spark plug seats installed.


they are cast iron heads, so I will spray some wd40 on them then. What do you mean the plugs might break, but the head will be fine? Do you mean with the cast iron head, I can pretty much use alot of force to get them out without risk to the heads themselves?
 
I would use a better penetrant like PB Blaster. wd40 doesn't really do much. Hopefully the heat idea will take care of it.

..Oh, and when you put the new plugs in, put some Anti Seize grease on the threads.