Factory installed spark plugs 1968 BB cast iron heads.
 

Everything I have points to AC 43N plugs.
Question is what version.
Some examples of different types.
Read some info on copper to aluminum gaskets happening in 1967?

Bought 30 of the 46N's for thirty bucks so they are usem up mules.
Ran them in past in everyday drivers where cutting edge performance was not an issue.
They ran many miles.

There are more versions but these are already bought and I await info here before buying more.

Thanks
Dave

Pic 1 is a "FIRE RING" example with copper gasket and 4 equal green rings.
Pic 2 is a "FIRE RING" example [46N] with aluminum gasket and wide top green ring.
Pic 3 is a "FIRE RING" set with copper gaskets and 4 equal green rings.

This may help.
46N's are the only ones here so far.
Aluminum gaskets and box dates of 76?.

Some more shower up today.
Aluminum gaskets, 4 even green rings and boxes dated "7"?

These were supposed to be with post 3.

43N'S and 44N'S still coming.

Looking for info in the right place helps.

Looks to me I have the proper factory plugs for 68 BB with cast heads.

Search over.

Enjoy or ignore.
Choice is yours.

Pic 1 from 1958. Note no green rings
Pic 2 from 1962
Pic 3 from 1966
Pic 4 from 1967
Pic 5 from 1968
Pic 6 from 1969 and it also has good info
Pic 7 from 1969
Pic 8 from 1970
Pic 9 from 1976 and shows wide top green ring. 1974 does not.
Pic 10 Dec 1970 and shows introduction of HI PERF plugs

,,,,,

These take care of "OLE BLUE" for life.
69 L78.
3 sets and early ones.
Note "NEW" that is not there on later ones.
Wide top green band is post 1974 at least.

Pic 4 is $15 total worth of usem up filters