When converting your S14 from the Zenki (early period) style front end to a Kouki (late period) style front end one of the components deemed necessary for the swap is the headlight brackets. These brackets attach to the upper and lower radiator supports at the front of the car and provide a location for the inner edge of the headlights to bolt to.
For whatever reason the replacement headlight brackets for most S-Chassis (even S13 Silvias) is about $25 per bracket new from Nissan. However, for the S14 kouki brackets they charge closer to $80 per bracket. This makes for a particularly pricey hunk of metal. The differences between the brackets and whether or not the zenki brackets can be modified to work with kouki headlights has been highly debated.
During my conversion I had both brackets side by side which allowed me to take some pictures and perform a direct comparison. Here is what I discovered.
The location of the bolt holes near the top is the only real difference between the two. The top headlight bolt hole is in exactly the same spot on both brackets. I even measured it with a pair of calipers to confirm and they were only off by about 5/100ths of a millimeter (I tried to get a pic of the caliper readings but the contrast was so low they didn’t come out sadly). You’ll notice that the pinch weld to the right is slightly askew on the kouki bracket, I didn’t realize it until I was looking at the pictures but the top portion of this bracket was welded slightly crooked (my other kouki bracket wasn’t like this). so whatever minor spacing differences there are in the top bolt placement, they’re well within manufacturer’s tolerances.
Modifying zenki headlight brackets for kouki headlights:
Both the kouki and zenki headlights are held to the bracket by 2 vertically aligned bolts. between these bolts there is a little plastic “nub”, this fits into the oval hole on the bracket. On the zenki bracket the oval “nub-hole” lines up nearly perfect for use with the lower bolt hole on the kouki headlight. This however leaves no place for the kouki headlight “nub”. You can see I used a sharpie on the zenki headlight bracket marking the area where you would need to drill out for the kouki headlight nub. That is all that must be done to bolt kouki headlights up to zenki headlight brackets.
Modifying zenki headlight brackets for the kouki bumper retainer:
The lowest bolt hole on the kouki bracket is used for the kouki bumper retainer. This is the metal strip that helps keep the upper edge of the bumper properly aligned. The zenki bumper retainer does not attach to the headlight brackets, thus there are no bolt holes for it. Unfortunately the lowest bolt hole on the zenki headlight brackets it too high for the kouki bumper retainer bolts, there for new holes will need to be drilled. I would recommend bolting the retainer to the fenders and the bumper reinforcement bar and then once it’s in place drilling the hole on the headlight brackets to properly locate it. Arguably the arms that attach to the headlight brackets are superfluous anyway since the zenki front end doesn’t have them and doesn’t seem to have any alignment issues because of it.
To further confirm the alignment of the upper bolt hole I performed a simple comparison where I aligned the two brackets “face to face” and then confirmed that I could see clearly through both brackets at the same time.
As you can see the upper holes line up flawlessly, the “nub-hole” on the zenki bracket is just a hair higher than the lower headlight bolt hole on the kouki bracket; but definitely usable with almost no modification. you can also see this is how I traced the outline for adding a new “nub-hole” to the zenki bracket.
I ended up using the kouki brackets for my conversion, since I already had them and I already went through the trouble of drilling out the welds to remove the zenki brackets. In the end it’s just as much work either way since the only way to install the kouki brackets are by drilling out the spot welds on the upper radiator support and replacing them with bolts through new holes on the top of the kouki brackets. Either way modification of the brackets is required, and at least if you were to modify the zenki brackets your modifications would be hidden behind the headlights. If I were to do this over again I would choose to simply modify my original zenki brackets.