I have a 1998 EXT 580 efi that has a toasted crank and crankcase. I went to Alphasports.com to check part numbers, as there have been a few older 580 parts advertised on here. I found the crankshafts were all the same. Unfortunately, the cases weren't. All 1995 and earlier, and some '96 550 and 580 engines had one number. Some 1996s, most '97 and '98 models used a 2nd number, and only the 1997 ZR 580EFI and '98 EXT 580EFI used a 3rd. A newer part number replaced the first 2 numbers, but not the 3rd I have. What the heck? :banghead: The '00-'02 550/580 models used a 4th number that replaced the origional number for my engine.

Can anybody tell me from experience what the differences were and why? I had always assumed total interchange of parts in this series of engine was a given. Am I wrong.

Thanks in advance for your time and help.

Here is all the models that a 580cc and a 550 cc will interchange




Part Number: 3005-406
Replaces: 3003-928 and 3004-882 and 3005-045
1999 BEARCAT WT (99BCD-1999) - CRANKCASE ASSEMBLY
1999 PANTHER 550 (99PAB-1999) - CRANKCASE ASSEMBLY
2000 BEARCAT WIDE TRACK (S2000BCCWTUS-2000) - CRANKCASE ASSEMBLY
2000 PANTHER 550 (S2000PACAAUS-2000) - CRANKCASE ASSEMBLY
2000 ZL 550 ESR (S2000ZLCERUS-2000) - CRANKCASE ASSEMBLY
2001 (S2001BCCWTUSL) (Bearcat Wide Track) - CRANKCASE ASSEMBLY
2001 (S2001PACCAUSG) (Panther 550) - CRANKCASE ASSEMBLY
2001 International (S2001BCCWTOSL) (Bearcat Wide Track) - CRANKCASE ASSEMBLY
2001 International (S2001PACCAOSG) (Panther 550) - CRANKCASE ASSEMBLY
2001 esr (S2001ZLCDEUSB) (ZL 550) - CRANKCASE ASSEMBLY
2001 esr International (S2001ZLCEROSB) (ZL 550) - CRANKCASE ASSEMBLY
2002 Bearcat Wide Track - CRANKCASE ASSEMBLY
2002 Pantera 550 - CRANKCASE ASSEMBLY
2002 ZL 550 - CRANKCASE ASSEMBLY
2003 Pantera 550 - CRANKCASE ASSEMBLY
2003 ZL 550 - CRANKCASE ASSEMBLY
2004 Pantera 550 - CRANKCASE ASSEMBLY
2005 Pantera 550 - CRANKCASE ASSEMBLY


Part Number: 3004-882
Replaced By: 3005-406
1996 EXT 580 (96ETA-1996) - CRANKCASE ASSEMBLY
1996 EXT 580 EFI DX (96ETE-1996) - CRANKCASE ASSEMBLY
1996 EXT EFI (96ETB-1996) - CRANKCASE ASSEMBLY
1996 EXT EFI MOUNTAIN CAT (96ETC-1996) - CRANKCASE ASSEMBLY
1996 EXT POWDER SPECIAL (96ETI-1996) - CRANKCASE ASSEMBLY
1996 PANTERA (96PTA-1996) - CRANKCASE ASSEMBLY
1996 ZR 580 EFI ETT (96ZRK-1996) - CRANKCASE ASSEMBLY
1997 BEARCAT WIDE TRACK (97BCD-1997) - CRANKCASE ASSEMBLY
1997 COUGAR (97COA-1997) - CRANKCASE ASSEMBLY
1997 COUGAR MOUNTAIN CAT (97COB-1997) - CRANKCASE ASSEMBLY
1997 EXT 580 EFI (97ETB-1997) - CRANKCASE ASSEMBLY
1997 EXT 580 EFI DLX (97ETE-1997) - CRANKCASE ASSEMBLY
1997 PANTERA (97PTA-1997) - CRANKCASE ASSEMBLY
1997 PANTHER 550 (97PAB-1997) - CRANKCASE ASSEMBLY
1997 POWDER SPECIAL (97ETI-1997) - CRANKCASE ASSEMBLY
1998 BEARCAT WIDE TRACK (98BCD-1998) - CRANKCASE ASSEMBLY
1998 COUGAR (98COA-1998) - CRANKCASE ASSEMBLY
1998 COUGAR DELUXE (98COB-1998) - CRANKCASE ASSEMBLY
1998 COUGAR MOUNTAIN CAT (98COC-1998) - CRANKCASE ASSEMBLY
1998 EXT 580 EFI DLX (98ETE-1998) - CRANKCASE ASSEMBLY
1998 PANTERA 580 (98PTA-1998) - CRANKCASE ASSEMBLY
1998 PANTHER 550 (98PAB-1998) - CRANKCASE ASSEMBLY


Part Number: 3003-928
Replaced By: 3005-406
1992 EXT (0650-187-1992) - CRANKCASE ASSEMBLY
1992 EXT MOUNTAIN CAT (0650-189-1992) - CRANKCASE ASSEMBLY
1992 EXT SPECIAL (0650-188-1992) - CRANKCASE ASSEMBLY
1992 PROWLER SPECIAL (0650-197-1992) - CRANKCASE ASSEMBLY
1992 EXT EFI (0650-217) - CRANKCASE ASSEMBLY
1993 440ZR (0650-247-1993) - CRANKCASE ASSEMBLY
1993 580ZR (0650-248-1993) - CRANKCASE ASSEMBLY
1993 EXT 550 (0650-257-1993) - CRANKCASE ASSEMBLY
1993 EXT 580 MOUNTAIN CAT (0650-265-1993) - CRANKCASE ASSEMBLY
1993 EXT 580 Z (0650-255-1993) - CRANKCASE ASSEMBLY
1993 EXT EFI (0650-236-1993) - CRANKCASE
1993 EXT EFI MOUNTAIN CAT (0650-237-1993) - CRANKCASE
1993 PANTERA (0650-222-1993) - CRANKCASE
1994 CHEETAH 550 (0650-310-1994) - CRANKCASE ASSEMBLY
1994 EXT 580 (0650-280-1994) - CRANKCASE ASSEMBLY
1994 EXT 580 MOUNTAIN CAT (0650-293-1994) - CRANKCASE ASSEMBLY
1994 EXT 580 MOUNTAIN CAT WAVE (0650-313-1994) - CRANKCASE ASSEMBLY
1994 EXT EFI (0650-281-1994) - CRANKCASE ASSEMBLY
1994 EXT EFI MOUNTAIN CAT (0650-282-1994) - CRANKCASE ASSEMBLY
1994 EXT EFI MOUNTAIN CAT WAVE (0650-314-1994) - CRANKCASE ASSEMBLY
1994 PANTERA (0650-283-1994) - CRANKCASE
1994 ZR 440 (0650-289-1994) - CRANKCASE ASSEMBLY
1994 ZR 580 (0650-290-1994) - CRANKCASE ASSEMBLY
1995 BEARCAT 550 (95BCC-1995) - CRANKCASE ASSEMBLY
1995 COUGAR (95COA-1995) - CRANKCASE ASSEMBLY
1995 COUGAR MOUNTAIN CAT (95COB-1995) - CRANKCASE ASSEMBLY
1995 EXT 580 (95ETC-1995) - CRANKCASE ASSEMBLY
1995 EXT EFI (95ETA-1995) - CRANKCASE ASSEMBLY
1995 EXT EFI MC DEEP LUG (95ETE-1995) - CRANKCASE ASSEMBLY
1995 EXT EFI MOUNTAIN CAT (95ETB-1995) - CRANKCASE ASSEMBLY
1995 EXT POWDER SPECIAL (95ETD-1995) - CRANKCASE ASSEMBLY
1995 PANTERA (95PTA-1995) - CRANKCASE ASSEMBLY
1995 PROWLER 2-UP (95PRA-1995) - CRANKCASE ASSEMBLY
1995 ZR 400 (95ZRA-1995) - CRANKCASE ASSEMBLY
1995 ZR 580 (95ZRG-1995) - CRANKCASE ASSEMBLY
1995 ZR 580 EFI (95ZRB-1995) - CRANKCASE ASSEMBLY
1996 COUGAR (96COA-1996) - CRANKCASE ASSEMBLY
1996 COUGAR 2-UP (96COC-1996) - CRANKCASE ASSEMBLY
1996 COUGAR MOUNTAIN CAT (96COB-1996) - CRANKCASE ASSEMBLY
1996 ZR 580 (96ZRD-1996) - CRANKCASE ASSEMBLY
1996 ZR 580 EFI (96ZRC-1996) - CRANKCASE ASSEMBLY

Thank you snow800! That was a most detailed answer. I printed it off for my future use. There is always somebody to hepl with this stuff on here. I think I need to become a contributing HCS member.

Much appreciated.

-Les