[Safari Larry]

The switch from brass to stainless was made December 1955 so early 56 tubes were brass. I have a set of 56 heads with the stainless tubes but can't get them out. I'll diddle with it some more today and see if I can make any progress. I doubt the 57-59 tubes will fit in the 55-56 heads but I don't know that for certain. I will check if I can get the tubes out of the 56 heads.