ZZP now offers a premium serpentine belt for nearly every configuration you can have.  We carry them in 6 and 8 rib widths, however you will need our 8 rib conversion kit to convert the supercharger belt to 8 rib.

Supercharger belts:

667 - Gen 5 blower stock belt GTP/GS/SS supercharged with stock 3.8" pulley (67 1/4" -1708mm)
663 - Gen 3 blower stock belt GTP/GS/SS supercharged with stock 3.8" pulley (66 7/8")
660 - GTP/GS/SS supercharged with 3.3 - 3.7" pulley (66 3/4")
658 - GTP/GS/SS supercharged with 3.2 - 3.6" pulley (66 3/8" - 1687mm)
653 - GTP/GS/SS supercharged with 3.1 - 3.5" pulley (65 7/8")
650 - GTP/GS/SS supercharged with 2.8 - 3.1" pulley (65 1/2")
716 - Bonneville SSEi, Park Ave, or Riviera with a 3.4" pulley
721 - Bonneville SSEi, Park Ave, or Riviera with stock supercharger pulley (72 5/8" 1845mm)

Stage 2 or 3 Intercooler
685 - 3.3"+
680 - 2.90" - 3.20"
675 - 2.6" - 2.8"
721 - 3.0" Using idler bracket from Bonneville SSEi, Park Ave, or Riviera 

Short Stack intercooler
675 - 3.5" pulley
672 - 3.3"-3.4" pulley
670 - 3.2" pulley
667 - 3.0" pulley

Accessory belts
915 - Stock accessory belt for Series II '99-03 (works with either UD WP pulley or OD alt pulley but not both) (2340mm)
919 - 99-03 Accessory belt with WP UD pulley 92 3/8"
923 - Accessory belt for Series II '99-03 with UD WP pulley and alt UD pulley (2360mm)
905 - Stock accessory belt for 04+ Grand Prix/ 04+ Monte Carlo/ Impala
935 - Stock accessory belt for 97/98 -or- 04+ Monte with Alt relocation kit (94" - 2367mm)
938 - Accessory belt for 97/98 with both under drive pulleys (2400mm)

SS M90 supercharger kit for L36
970 - SS M90 for 97/98
956 - SS M90 for 99+ 4.0"- 4.2" pulley
947 - SS M90 for 99+ 3.5"-3.8" pulley

Meziere electric water pump
875 - 99-03 accessory belt with Meziere electric water pump
864 - 04+ accessory belt with Meziere electric water pump
895 - 97/98 with Meziere electric water pump