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ray_mcavoy · 11-02-2012, 11:20 AM

Hi Desert,

Here's a sketch I made off the original trim holes on Dad's 77.

As I mentioned in my earlier reply, we substituted several of the stud/nut type fasteners for the stick-on ones so the above sketch doesn't show all of the holes that were there from the factory. The front fenders are where we did most of the substitution but I did drill a couple holes in front/back of the wheel opening (similar to K & L on the bedsides) that aren't shown on the sketch. Also, the bedsides originally had some additional holes (not shown) on the sides back near the tail lights that took snap-in clips (we substituted those for stick-on ones as well).

Another thing that's important to note is the fact that the screw holes (A, B, C, D, and M, N on my sketch) seem to vary in position side-to-side a little bit depending on the molding. And the location of those holes is critical since the screws go right through the pre-stamped holes in the molding, leaving no room for adjustment.

I started by marking out the original locations (from the sketch) with a Sharpie marker on the primer. Then I held the new molding up against the truck and noticed that some of those screw hole locations were off a little ... around 1/16" to 1/8" or so. So I re-marked those screw hole locations on the truck using the new moldings as a guide. I should point out that we were using NOS GM moldings so if the screw holes on those were off a little as compared to the truck's original moldings, I wouldn't be surprised if the aftermarket pieces are off a bit as well.

In addition to those screw hole locations being critical, the height of the holes for the snap-in clips (I and J) as well as the ones we left off (substituted w/stick on clips) back near the tail lights is also important since you can't move the clips up/down on the molding and you can't drill the holes oversize or the clips won't fit securely into place. The side-to-side position of those holes isn't quite as important since you can slide the clips along the molding a little to compensate. And the holes for the stud/nut type clips can be drilled slightly oversize to allow for some fine tuning of the molding position.

11-02-2012, 11:20 AM	#10
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,379	Re: Body Moldings Hi Desert, Here's a sketch I made off the original trim holes on Dad's 77. As I mentioned in my earlier reply, we substituted several of the stud/nut type fasteners for the stick-on ones so the above sketch doesn't show all of the holes that were there from the factory. The front fenders are where we did most of the substitution but I did drill a couple holes in front/back of the wheel opening (similar to K & L on the bedsides) that aren't shown on the sketch. Also, the bedsides originally had some additional holes (not shown) on the sides back near the tail lights that took snap-in clips (we substituted those for stick-on ones as well). Another thing that's important to note is the fact that the screw holes (A, B, C, D, and M, N on my sketch) seem to vary in position side-to-side a little bit depending on the molding. And the location of those holes is critical since the screws go right through the pre-stamped holes in the molding, leaving no room for adjustment. I started by marking out the original locations (from the sketch) with a Sharpie marker on the primer. Then I held the new molding up against the truck and noticed that some of those screw hole locations were off a little ... around 1/16" to 1/8" or so. So I re-marked those screw hole locations on the truck using the new moldings as a guide. I should point out that we were using NOS GM moldings so if the screw holes on those were off a little as compared to the truck's original moldings, I wouldn't be surprised if the aftermarket pieces are off a bit as well. In addition to those screw hole locations being critical, the height of the holes for the snap-in clips (I and J) as well as the ones we left off (substituted w/stick on clips) back near the tail lights is also important since you can't move the clips up/down on the molding and you can't drill the holes oversize or the clips won't fit securely into place. The side-to-side position of those holes isn't quite as important since you can slide the clips along the molding a little to compensate. And the holes for the stud/nut type clips can be drilled slightly oversize to allow for some fine tuning of the molding position.