The chevelle frames are shorter then the GTO,El camino, Chevelle wagon, skylark, and F85/skylark chassis. the part on these frames that is longer is the the trunk section.
I have also noticed that some of the frames have two extra body mounts, there located next to the outer firewall mounts. The convertibles are boxed, as you guys know, and I believe the el caminos are too. I hope this helps you guys out.
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1965 GTO convertible
2009 GM Design Award winner
Triple black with Subtle yet massive Modifications.