I have a 76 F100 and I'm planning on installing the headlights of a 79 that I bought at the salvage yard. Are they the same as far as installation, because yesterday I try them on, but the bucket from the 79 ends up at an angle becasue the top attahcment of the 79 lights is longer than the bottom attachment, and the attachemnt from the 76 lights are the same length.

I tought the ligths could be use in either truck

Thanks for your info

 

I have not done this personally but many others have.
as far as I know? as long as you have everything from the 79,
all you need to do is drill some new holes? the buckets do attach differently, but will work with some minor mods

 

So I will need the radiator support as well, because when I look at the LMC catalog, the radiator support calls for the same number from 73-79 trucks.

 

You won't need a radiator support, unless the one you have is bad. I did a 79 to 75 swap last summer and all you have to do is drill new holes in the radiator support for the new buckets to go on. I just kept my grill frame and the headlight surrounds with the buckets that I wanted mocked up in place behind them. You can use clamps or zip ties to hold it in while you get all your measurements and got it looking good where you want it. Then you take a sharpie or something to mark where you want the new holes, take off the headlight surround and the mocked up bucket, drill where your marks are, drop in the speed nuts, put in the buckets and reassemble. Hope that helps. It will keep you from having to by a radiator support needlessly. It goes alot faster if you've got help.

 

Or you can just take the measurements off of the support at the salvage yard you got everything else from. I just held up a tape measure on a few key locations while I snapped pictures with my cell phone - no help, no paper or pencil, 1 1/2 minutes!

 

I just performed this exact swap, and it is as easy as it comes. The buckets are a direct bolt up, and once the top bolts are in, the bottom holes can be easily drilled. I found it easiest to remove the clips and drill the holes without removing the bucket. Once the holes were drilled, I re-installed the clips, and ran the bolte through.
It has taken almost as long to type this, as it did to actually perform the work.
Here is a pic that describes the two holes that need to be drilled.
There are also a few various install pics.
Image of more grill installation - Photobucket - Video and Image Hosting

 

Going from early to late is easy, as you've said. I was going from '78-79 back to '77, and my radiator support was not the original '77, so I needed my correct measurements.

 

That title messed me up. "79 headlights into a 76" implied that you were installing rectangular light is an older truck, but this is still just as easy.
Start with the lower fasteners. You still need to drill, and the new holes are 3.25" lower than that of the rectangular buckets.
Start by drilling two holes directly below the lowest holes for the 79 bucket. These holes are 3.25" below the original holes. You can see both sets in the "Link" I attached above.
This will locate the older bucket perfectly, and then you can address the upper two holes. This will be a piece of cake as well.

 

I didn't say you needed the rad support???? listen to 75F350 he just did it