When I bought my Z51 the air dams (below spoiler) had been removed by previous owner. I bought new ones from a Mid America Motorworks and they arrived in an OEM bag with the correct OEM part # (I think). Part# 84308943. This number also is cast into the RH part and the LH part is ...44. My first pic shows the back side of the LH part, showing the 3 holes. This part is supposed to be common for the Z51, GS and Z06, but the normal Stingrays have an alternate part # and is longer with 4 bolt holes. The parts I have measure about 10-1/4" in straight line and a bit less than 11" along the curve.
Here is my problem: I fitted the RH part and the outer two bolt holes line right up with the two speed nuts in the car's plastic underside, but the third bolt is way short the third speed nut. My picture also shows a 4th speed nut that is likely there for the normal Stingrays. There is a round hole close but not exactly lining up with the inner hole in the air dam with no speed nut. I don' want to start drilling my "new" car yet, but I guess I am willing to drill an extra hole in the air dam if necessary. Pictures show front and back of RH dam on the car with two bolts.
So, I am asking the Forum these questions:
1. Do I have the correct part number for my Z51?
2. If you have a Z51, GS or Z06, please measure your air dam vs. my numbers above.
3. Has anyone else had this problem fitting the air dams to a Z51?
Thanks in advance for your help!
Ken

LH part

Two unused speed nuts and parts 3rd hole not lined up to hole above.

outer bolt

front sie

 

Are there holes & they don't line up? On my base I replaced mine last month. On my set there were more holes on the pieces then holes under the bumper to bolt on. Everything still secured though & none the the 3 pieces will move around.

 

Third hole on piece is close to a hole under bumper but I would have to drill one of the two. The hole in bumper there does not have a speed nut, but there is one about 2" closer to center, as if the piece is too short.

 

The extra speed nuts are for base model cars that have an air dam go all the way across. I suggest drilling the rubber airdam to match the speed nuts for the 3rd hole. Just take 1 of the unused speed nuts and move it over to the right spot. The previous one probably fell off.

 

Bruno
As shown in my 2nd pic, the 3rd speed nut is past the end of the air dam. There is a simple round hole on bottom of car near but not close enough to match the hole in the air dam. I plan to drill a simple round hole in the air dam that lines up with the hole in the car. I'll use a speed nut that does not fix to the plastic but there is good access to hold it from behind to get it started.
Ken

 

You may need the other longer airdam. I wouldn't be surprised if GM installed the base ones on the Z51 on some.

 

I completed installation of the air dams, by drilling an additional hole in the air dams, only about 1/2" away from the third (inner) hole that was there. The hole above in the spoiler is just a simple round hole without a speed nut, so I used the type of speed nut that is not fixed on the back size. Because there is a hole in that upper panel at this location it is easy to reach behind to stop it from spinning until it grips the plastic.
Looks like the air dams I have are not the exact ones for my car. Come spring, I will know if they will be bottoming out anywhere along our rallies. If I decided to replace them, I will know better what to look for as far as length and bolt holes. Whatever aero improvement they provide will be working with what I have.
Thanks for your input.
Ken

 

Do some searching here. I remember that some models don't get the center piece while others do.

 

Fuzzy
That is my plan after I see how much road contact I have with this one.
Ken

 

i've searched, can't find anything about the center piece, not sure if it's missing or if not installed on my 2014 z51!!
thanks

 

Those are meant to be trimmed for Z51 use.

Should look like this:

 

mine does, thanks!! is this in print anyplace??

 

I had this saved from a few years back:

 

thanks!!