First project stripping an old engine and the spark plug in No.1 is stuck hard. Can I heat the Alum. head to assist in removal? any other tips?

Get some Rost Off and spray it onto the base of the plug, let it soak for a little while and try to turn it.Slowly move the plug backwards and forwards, and spray onto the base at regular intervals. Once it is out, coat the new plugs with anti-seize when you put them in.

Use a piece of tube which clears the ceramic part but contacts the hex part of the plug. A few gentle taps on the tube will generally break the stuck thread and allow the WD40 or Nutcracker to penetrate along the thread easier. Then continue as previous post.

Thanks guys will give it a go..

I use a copper anti seaize and it seems to work fine, as it conducts and also it will not form carbon deposits.

Larry,

I have worked on some really old stuff in my time - OK cut the jokes!
If the plug is really stuck, and you wish to save the threads in the aluminum head. Then you will have to drill the plug out to almost the thread size and then run a tap down. But, by all means try bashing, heating, twisting and swearing first!!

Yo may need to rethread anyway. Sparkplugs don't tend to get too badly jammed unless there was an awful lot of contamination or the plug has been crossthreaded. I hate crossthreaded sparkplugs