OK. I had to go back and look at my manuals to see what plugs are what.

My Toronado, Cadillac, and AD Chevy all specify AC-44 in their respective shop manuals. The Chevy manual actually specifies AC-44-5. Does that mean AC-44 or AC-45?

Whenever I tried to buy plugs for any of them, I've been told AC-44 are not available and that AC-43 is the substitute. The AC-43 is the plug that comes up for these vehicles when I try to buy them online from various places.

So... I did confuse AC-44 with AC-45 in my first post (which I have since deleted to avoid confusing the issue even further).

But, the question remains, which plugs are actually discontinued and which ones are still available, discontinued or not?

1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)