The early one is actually 7". I had one on my 67 383 Barracuda, also seen them on 67 Darts. I don't when they switched over, but the 7" is not rebuildable without major work to take the case apart.

The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it.

JB Rhinehart, Realist

A-Body's RULE!