Don't bother with any canopy for an 88-98 Chevy. The bed on those trucks tapers at the back. The width on the canopy matches at the front of the Dodge bed, but is narrower by about 2" IIRC. I looked at a canopy off of an 89 Chevy long bed and it was too narrow to work at the back of the bed on my 92.
Originally Posted by pulltilbroke
From my research, a canopy off of a 73-87 Chevy (91 in the R/V series) and a 74-ish to 97 Ford long bed should fit the 72-93 Dodge just fine. Bed widths and lengths are similar across those models are similar.
92 Dodge W250 regular cab, Cummins, 5 spd, 255/ 85R16 Toyo MT's, some other tweaking and changes.