Hopefully this will offer some clues.

Thanks

The reflection in the picture makes it a little difficult to see but the lid appears to be reproduction.

Some helpful links:

http://nastyz28.com/threads/1970-z28-air-cleaner.64687/

http://www.nastyz28.com/threads/nos-.../#post-3580098

The lid is a reproduction. As for the base. I'm still on the fence for my decision. I have never seen a over the counter base. Just originals. The stamp leads me to a reproduction. Maybe some who has a NOS over the counter can chime in and take this further. I'm going to say everything is reproduction. It's the stamped numbers that made my decision. They just dont look factory to me.

A few pics......Top pic show NOS over the counter lid

You guys are amazing.

looks like the whole thing may be a reproduction assembly?

Wanted: Original,OE,GM 70-71 Z28 Air Cleaner Base in "restorable" condition

Thanks BIG time guys....now I am going to play the devils advocate only because my buddy swears this is a GM part....maybe an over the counter part?

Whatever you decide is what I am going to hang my hat on, but he has some valid questions.

1. If you take the original GM breather and look at the style of crimping (the vertical lines) at the end of the snorkel next to the round body of the cleaner, it appears to be very similar to mine.

2. If you take the the original GM breather and look at the rolled up end of the snorkel, it is not a nice, crisp perfect lip as compared to the re-pop one which is too perfect. Then look at mine and it also appears to be less than a perfect rolled end.

3. If you take the the original GM breather and look at the snorkel where it is spot welded against the round body of the cleaner (next to the vertical lines), the two seams are not lined up perfectly, as they appear to be somewhat off set or spot welded poorly. My breather appears to be poorly lined up as well. Yet when you look at the re-pop, the butting of this seam appears to be almost perfect which seems to happen a lot on re-pop parts. Some times they are "improved" too much.

I am not trying to sell anybody on my OJ Simpson theory, but could my breather be an over the counter part or did I just end up with a re-pop part that my buddy will have to come good for?

Thanks again guys!!!

Here is my final opinion. The base is a later 1970 non notched or over the counter OEM base. The numbers appear to be hand stamped common with the early seventies GM. What the numbers mean is still open for discussion. The tool markings, seams and spot welds look OEM. The lid 100% is a reproduction due to the ramped outer edge. Anyone have any more to add to this I'm open to learn also?

The base looks correct, it has the correct metal crinkling. I’ve never seen a reproduction unit that has been able to replicate this. The snorkels are what concern me but I have seen GM original snorkels sold to repair damaged snorkels and they did not have notches in the seams, so a GM over the counter replacement is possible. I’ve only seen pictures of one over the counter GM replacement air cleaner and I think it belonged to Chuck. Maybe Chuck can compare.

Mike