Spark plugs?

So I bought a set of spark plugs for my 1970 350ci engine, but when I was middle of changing oil, I've found out that those didn't fit in to my heads. Then I remembered that back in 2009 autumn I had a problem with the heads. There was a tiny crack between cylinders 1 and 3. And the fix was back then just to buy used heads and install them on. So, now I have to find out what heads those are and buy new set of spark plugs to it.

The first month

So, first month with my baby. There has been little bit trouble when I was travelling to Jyväskylä. Blew intake gasket and oil leakaged over transmission and exhaust pipe, which lead to blueish smoke on my rear-view mirror. I took her to JMT-autopalvelu where they fixed the intake gasket, but noticed that #3 cylinder wasn't firing constant. They said that I could drive her back to Helsinki, but there were a risk that the trip could make things worse, so I deciced to leave her Jyväskylä, with JMT-guys. A week later they called and told me that also the head gasket was blown too and there was a hairline crack on the head's waterchannel between combustion chambers. So I told them to look for a set of used heads. Yesterday I called them again to see what was the situation with my baby, and they were busy, so I didn't get my baby for the weekend. So, monday or tuesday I'll have my baby back.