73-87 Chevy _ GMC Trucks > Performance

Air Deflector Theory

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JohnnyPopper:
So it looks like factory installed these starting in 81'?

Is the theory to keep air from going under the cab/truck thus reducing turbulence/drag?

I get that concept, when I did 125 in my Olds Toronado she lifted up about 4"!

I also see the good results from Freight Containers having the side wings.

But with these flat faced trucks, it raises a question about increasing the overall surface coming in contact with the the air.

I bought a 5" version, at high speeds it seems to vibrate.

Any thoughts would be appreciated.

VileZambonie:
These were available for all years and served as an air dam as well as a way to hide the ugliness of the front suspension. I had one and it made no difference on my 1980 other than hid the control arms a bit.

JohnnyPopper:
Thx VZ, the earliest I could find was for a '81, so I made the leap and bought it. Doesn't really fit my '78 bumper profile perfectly.

I think I'm going to remove it and see if the vibration goes away.

75gmck25:
I ran across one of those "what changed each year" articles for square bodies and it said the front deflector under the bumper was not available until '81.  That was the same year they made some other front end changes, so it makes sense.

JohnnyPopper:
Ahhh, thx!

Found out the vibration was a smoked inner right front bearing, that I had just paid a shop to repack before a trip to WA. Can't find good help these days.... ::)

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