Is there a differences between the big block Z bar and a small block? If so what are they? How can I tell which one I have now?
Thanks in advance- Tony

Assuming you are refering to '67-'69, the bb bar is about 9-5/8" across, sb 9.0".

Worthy of note is that the '67 Z-bar frame bracket is slightly different than '68-'69.

William, thanks for the info it is just what I was looking for!