It surely seems there are many opinions on what is correct for a given era when it comes to these filters. Within the National Corvette Restorers Society, there is a general consensus that, based on seen AC engineering data, the square mesh probably started around the end of model year (MY) 1969 or the beginning of MY 1970. That is to say, somewhere around the beginning of calendar year 1970. I will try to secure said data if I can and post it here when I do.
I wanted to post a few pictures of a NOS filter I purchased for my 1969 Camaro. I bought this from a fellow named Pete Lindahl in New Mexico. Pete is highly regarded by those of us in NCRS as a knowledgeable enthusiast and I'm sure many on this board who know him will agree.
If anyone has any pertinent data to share on these filters I'm sure all of us would appreciate it. Hopefully we can all learn a little more.
The entire box was there but in horrible shape. I cut the date away and saved it.
Notice the verbiage as well as the groove cut around the entire circumference. This groove is evident on the front and back.
Again, the groove on the back as well as embossed A212CW.
A close up of the front groove.
A close up of the rear groove and embossing.
Very heavy gauge external screen and overlap. Also notice how heavy the oil wetting is.
Backside screen and overlap.
This is what I have for a unit manufactured on the pictured date. Anyone else?
Regards,
Mark