Qeaflex, check out
www.rigrite.com
You probably need a Z-1112 deck plate, which fits both the z145 and z170 section.
If it's your mast foot that needs replaced, you can find section dimensions here:
http://www.rigrite.com/Spars/Zspar/Z_Mast_specs.html for both the 145 and 170, and you should be able to measure your existing mast to determine which it is.
And then hope it's a 145, because it looks like feet for the 170 are no longer available. The Z-145-SF foot comes in different sizes - which should be heights, in case you needed to cut some of the foot of the mast, you could get a taller foot so that you wouldn't have to shorten your rigging.
I couldn't tell you directly which section you have, as I have a Dwyer mast.
Brian