Will the front clip of a 1993 Chevy 1500 pickup bolt on to 1991 GMC 2500 pickup?

No, a 1993 Chevy 1500 front clip will not directly bolt onto a 1991 GMC 2500 pickup. While they share some similarities being GM trucks of a similar era, there are key differences:

* Body Style Variations: Even within the same year, there can be subtle differences in body mounts and sheet metal between 1500 and 2500 series trucks. The 2500 is a heavier-duty truck and has a different frame.

* Grill and Headlight Variations: The grilles and headlight assemblies are different between Chevy and GMC, and even between 1500 and 2500 series.

* Frame Differences: The 2500's heavier-duty frame will likely have different mounting points and dimensions compared to the 1500. This is a major obstacle.

You might be able to *adapt* some parts, but a direct bolt-on swap is highly unlikely and would require significant modification, likely making it more trouble than it's worth.