Sorry it took a while to respond to all of you... work has consumed most of my days. Anyhow I thought I would upload a couple pics and share what i found should others have this issue.
1st ) After ordering from numerous vendors & returning a few sets which I could tell were already opened and probably returned for similar reasons, I finally came to the conclusion that all of the ones i got my hands on appear to be produced by the same parent company.
2nd ) I went through all the possibilities why these header moldings were not falling far enough over the forward edge and under the windshield moldings themselves...
a.) is windshield high enough or thick enough when installed? I used 3/8" butyl tape to install the w/s b.) is there something under the header moldings causing them not to sit flush on top of the header frame (across the top of the "A" Pillars? After the second set I verified that there were no spot welds or other reasons they were not sitting flush (my windshield frame was original). c.) is there a reason why the windshield moldings may not be up high enough to cover the header moldings? This was, i believe, one of the reasons I had an issue. I decided to check out a couple resto companies and see what was offered in the area of Windshield molding clips. I purchased mine from Perf Years since they were right around the corner from where i live. In this case I don't recall more than one option. Unfortunately my buddy had installed the Windshield after we painted the car and I don't believe we saved the orig molding clips. I decided to check out a couple other vendors which provide parts for all F-Bodies and came across a separate listing with Firebird Central, one for coupes and one for convertibles. Looking at the pic on their site raised my hopes since the difference in overall clip height seemed noticeable. I ordered a set. You can see a noticeable diff side-by-side. I installed these convertible w/s/ molding clips, the header moldings, and the W/S molding clips. This provided me an improved result, but not a 100%. Two noticeable defects. One is where the two halves of the Header moldings overlap and the second is how the W/S moldings bow up in certain area's and seem extremely tight (pulled close to the w/s) in the center section. Alas, I am done playing with this (shed enough blood & sweat). The defects are only noticeable if I point them out or you are looking for it. But if someone has some remedies for the issues I am pointing out let me know. BTW, I also purchased a second set of W/S molding hoping a different vendors would fit better. Albeit, while at the Camaro Nationals we went around critiquing everyone's header molding to w/s moldings and i can honestly say that 3 out of 4 were not much better than mine. The onus i still believe is on the Header Moldings themselves, but using the correct clips help also. I'm wondering if anyone has a set of original w/s molding clips we could check the height on for comparison. Also, maybe check the depth of the forward edge of a set of original header moldings.
