bastereo, there are two distinctly different versions. One is standard, and the other is with AC. (the AC unit's top half of the dip stick will come up along side the valve cover between that and the compressor and will be almost as high as the top of the valve cover)

But the standard non AC one will come up between the manifold along the side of the head.

There should be a lower piece that is in the block from the bottom, and goes through a tapered slot/hole in the windage tray (if applicable) and up into the block. Then the outer piece is pressed in to the block from the outside and essentially the two mate in the block so to speak. And the dip stick goes into this outer piece.

BUT... it is hard to determine how far the lower half protrudes from the block, and the same for the outer half? And if they do fit/press together (one slightly inside the other) how far do they go in... did I get them far enough in, not far enough etc? And then there seems to be different lengths, and different length dip sticks...

On the Engine Cooling and Oiling page, #20 & #41:
http://www.1968firebird.org/illustrated/illeng/illeng4_v8.jpg

Something that I have never found any concise information on as of yet? Maybe Q or Tom have some insight for us on this topic? But this is why I had to fill it with 6 qts, run it, let it sit, and then... Mark my Dip Stick where FULL was! That way I knew for sure where the mark was with my particular combination of miss matched parts.

Hope that all makes sense?

Brett - 67 Drop Top 455!