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Chevy Grille Swap - Front Clip ConversionAging Your 1973-1979 GM Fullsize From the March, 2009 issue of 4Wheel & Off-Road
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 '74? '79?  Our grille conversion will...  Our grille conversion will give you the info on whats needed to use either an older or a newer grille, but in this case we put a 73-74 grille on a 77 truck. The first step is to unscrew the plastic grille, which should be held in with about eight Phillips screws. Youll also end up removing the headlight buckets as well as the header panel, center vertical support, and side grille brackets. It seems metric bolts were phased in about 1976 or 1977, so make sure you have a 10mm socket before you start.  We couldnt find any...  We couldnt find any junkyard trucks newer than 1976 that didnt have a cable-release hood latch. Our cable had broken, and we wanted to eliminate it for safetybut you may want to add one for security. Either way, the two latch designs require a different header panel. The striker on the hood also needs to be changed to match the hood-latch style. The bolt pattern on our hood was the same, so it was no big deal. We also found the external hood-latch handle was located in a different place for each grille style, which is what prevents easy swapping of 73-74 grilles with 75-76 units. The chrome trim on the header panels are removable via 3/8 nuts on the back. Strangely, the holes were drilled in different places on the 74 unit we used, but we were able to slide the studs on the trim to make them line up properly. There are two designs of chrome trim, 73-78 and 79-80.  Another difference between...  Another difference between years is where the horns are mounted. Its an easy deal to drill two new holes per side in the 74 header panel to make the 77 horn brackets fit. Whyd they bother changing stuff like this from year to year? An emissions stocker on the header panel can help you identify vehicle years if youre confused.  The vertical center support...  The vertical center support is also a different shape to clear the more sunken-in 74 grillethe 77 unit is on the right, the 74 on the left.  The 77 uses these side...  The 77 uses these side brackets to support the grille, but they can be easily unbolted. It would be tough to retrofit them to the core support of an older truck. The core supports for the 73-76 trucks we saw had nonremovable grille brackets at both sides of the radiator. Swapping them onto the 77 would require changing the entire core support, so we just skipped it and hung the grille with fewer screws. The 73-76 grille brackets didnt look like theyd get in the way of installing a newer 77-79 grille.  The 74 grille needs...  The 74 grille needs to be screwed to two bolt-on side brackets that are mounted close to the headlights. We took the brackets from the donor vehicle and found that our core support had dimples where the holes needed to be drilled to mount them.  All the 73-79...  All the 73-79 grilles we saw used small, white, nylon bushings for the grille screws to thread into. Most of ours were brittle, stripped, or missing, so collect a handful while youre at the junkyard. Wed heard that interchanging the grilles among 73-80 square-front-clip-style Chevy trucks is a simple bolt-in deal. Just choose the grille you like best and swap at will. Wrong. Thats what we learned when a project that began with a broken hood-release cable on a 77 Chevy resulted in a swap to a 74 grille. During the junkyard tours that ensued, we found out a lot about the different components used for the first three versions of grilles on these trucks: 73-74, 75-76, and 77-79. We couldnt find a junked 80, so thats where our info dries up. We also wont swear that Chevy didnt use more configurations than what are shown herein fact, we know 77-79 grilles came in three different colors, and there were two different styles of headlight doors. So there may be variations, but this story will at least let you know what to look for if youre in the mood to revamp your 73-79 ride with an older or newer grille. We used junkyard parts for the swap and spent about $42. Youll have to do the same since all we could find thats still available new are the 77-80 grilles, headlight doors, and chrome trim around the grille. Converting from a square front clip (73-80) to a sloped front clip (81-91) is also popular, especially if you like the small rectangular headlights on the 88-91 Blazers and Suburbans. That swap is more complicated since it involves changing the entire front clip, including the fenders, inner fenderwells, hood, and core support.
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