'85-'88 base rad support vs 89-'91 base rad support

[Irish1941]

Is there any real big differences on the single headlight supports from 85-88 to 89-91 in the R/V trucks?
Never had the two side by side. They use same headlight bucket and pretty sure grille mounts use same holes.
GM lists different part numbers so must be different somehow...
Signal light mounts?

[83GMCK2500]

I did a little digging and now I'm very curious as well. From pictures it looks like the front signal/markers have the same mounting dimensions. My initial thought was the air intake, that the hole/knockout between radiator opening and headlight divot was different, cannot confirm. Like you said, need to have the two right next to each other.

[Irish1941]

The air intake is in same spot. That never changed location no matter stacked, side by side, single headlight or big/small block. That much I do know.

Compared 87-88 grille mounts to 89-91 and they are in same spot.
89-91 single headlight bezel uses one screw on top vs two for earlier one but that can't be the only reason.
Looking at them, I agree the signals use same mounting points.

The 89-91 support is 15628622 and 85-88 is 15606587.
83-88 headlight assembly is 5968097. Same number for 89-91.


Maybe it is just a matter of new series truck meant new part number?
I have a truck that was swapped to GMC quad headlight and Im trying to go back to the 89-91 single headlight. Have all parts just not the rad support.

[cochino12]

Originally Posted by Irish1941

The air intake is in same spot. That never changed location no matter stacked, side by side, single headlight or big/small block. That much I do know.

Compared 87-88 grille mounts to 89-91 and they are in same spot.
89-91 single headlight bezel uses one screw on top vs two for earlier one but that can't be the only reason.
Looking at them, I agree the signals use same mounting points.

The 89-91 support is 15628622 and 85-88 is 15606587.
83-88 headlight assembly is 5968097. Same number for 89-91.


Maybe it is just a matter of new series truck meant new part number?
I have a truck that was swapped to GMC quad headlight and Im trying to go back to the 89-91 single headlight. Have all parts just not the rad support.

I just pulled my 91 support, you are welcome to it if you can figure out a way to pick it up

[Irish1941]

Whoa! That's awesome of you to offer it up.
I could try and see if I can get a friend to pick it up.
In meantime, think you could snap a picture of the front of it?

[Wwes]

I have a new 89-91 support sitting beside the original 83 support. Will get side by side pics when I get home.

I don't think the air intake is in the same place, because on the 83 it is in the location where the inner headlamp would be on the 89-91.

[Irish1941]

Originally Posted by Wwes

I have a new 89-91 support sitting beside the original 83 support. Will get side by side pics when I get home.

I don't think the air intake is in the same place, because on the 83 it is in the location where the inner headlamp would be on the 89-91.

I should have been a little more clear.
89-91 air tube goes into a vertical air box instead of an actual hole thru the support but is still in same spot as earlier support air intake hole.
The air box blocks the inner headlight on the side by side 89-91 grille. That being said, you're technically correct. I'll post some pix when I get a chance of my trucks.

I dug deeper into parts book on this, and I'm thinking only difference is the air box vs the direct hole & diffuser on earlier supports.
Parts book list air tube and box as only for 89-91 and just tube for '88 and down. No reference to V22 chrome grille vs non V22 grille.

[Wwes]

Originally Posted by Irish1941

I should have been a little more clear.
89-91 air tube goes into a vertical air box instead of an actual hole thru the support but is still in same spot as earlier support air intake hole.
The air box blocks the inner headlight on the side by side 89-91 grille. That being said, you're technically correct. I'll post some pix when I get a chance of my trucks.

I dug deeper into parts book on this, and I'm thinking only difference is the air box vs the direct hole & diffuser on earlier supports.
Parts book list air tube and box as only for 89-91 and just tube for '88 and down. No reference to V22 chrome grille vs non V22 grille.

Ok good, I was thinking of what I'd need to get my snorkel lined up.

I'm getting ready to do the headlight conversion to a later crew cab setup as well.