I have a pair of SHO Shop linear springs, fronts only, for 89-95 SHOs. Make an offer before they go on eBay. These springs are used, in excellent condition, never altered or cut.
These springs take the front end of a Gen1 or Gen2 SHO about as low as you dare go. I do not know the lb/in rate but it's high. These springs would be best on a track car. On the street, IMHO, they're too much.
Note they do require a higher-rate damper such as Tokico or Koni. Again IMHO Tokicos don't keep up with these springs. On a track car with Konis turned up firm, they'd be fine.
Also note, these springs lower the front so much that an alignment kit may be needed to obtain satisfactory camber.
Joseph van Oss