Air dam???

[zieg85]

Does anyone know what the original purpose of the air-dam (plastic piece mounted (to-below) the front bumper) typically on the mid-80's 1/2 ton trucks???  I am assuming it is for aerodynamics or cooling.   

[VileZambonie]

both and probably a little bit for looks.

[Toolmaster]

In 1978-83 I worked for a GM dealer parts warehouse. All parts have a group # as well as a group name.
The best I can remember that part came under Fillet. I was told it was just that, a filler made up to fill a space that wasn't given much time in design. Pushed off to the designer's with more time that needed something to do. Later on GM started to pay more attention to the area. I cant prove any of this as fact, and it's been over 30 years ago, I could be wrong.

[zieg85]

I thought I would see if anyone knew for sure.  I guess I'll try it both ways.  My upcoming project had a busted up one on it which I removed and I have a good replacement off a parts truck.  I don't remember ever seeing one on a 20 series or above.  If it helps in wind shear for gas mpg, it would be nice to know. 

[Blazin]

Most of mine were busted when I got them so they got ditched. I am pretty sure the GVW didn't matter. My 86 2500 had one, my 86 K30 had one. the blind nuts are still on the bottom of the bumper. That and I like the looks better without them. My 86 K20 I bought in 88 was the only one I can remember that wasn't busted. I promptly took care of that the first night I owned it fourwheeling.

[zieg85]

AHHHHHHHHHH, very interesting.... 2 of my past 86's and my current 86 all had them.  My 2 85's I have now don't... and none of my other 81-84 had them.  Could it be an 1986 on up deal??

[Blazin]

I don't think so, but I am not sure as I have an 84 C20 That has the remnants of one on it.

[zieg85]

I don't think so, but I am not sure as I have an 84 C20 That has the remnants of one on it.

You are correct.  I found so pictures of GM ads going back to 1981 that had them.  They made the statement in one 1981 ad that mentions "new aerodynamic design" and "300 lbs lighter".  I should have researched this further though.  I am going to put my extra on my 85 C-20 and see if I can squeeze a little more mpg out of that 454, wish me luck...

[Bowtieogre]

I had one on my stock '80 C10 but I took it off when I lowered it. It looks factory but then again ive looked at parts catalogs and never seen one offered for anything mid 80s and back. I always assumed it helped keep the air moving thru the radiator and engine compartment properly.

[79diesel]

is this what you are talking about? kinda hard to make out but theres one on my 79

[zieg85]

http://www.73-87.com/7387info/ads_GM/85_pickup_your_life.jpg

It is kinda hard to see but yes, that is what I am talking about