I was just wondering how crack prone the 601's are.
Some of the light weight heads crack if you look at
them funny.I don't want to put time in to some if they are going
to crack right away if I over heat it or run it hard.

They aren't old smogger light weight castings. Not renowned for being crack prone. They've got a fair bit of meat to them.

Thanks thats what I was hoping to hear.
I will pick some up if I find them cheep.