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Supercharger Belt Selection Guide for the 2003-2004 Mustang Cobra

Please note that the information for this guide was obtained through 3rd party sources so use at your own risk. There are also size overlaps with certain pulley sizes. This Guide should be used as just that -- a guide.

Also, I cannot make recommendations on belt sizes because there are too many configuration possibilities. Thanks for understanding.

If you are using the new Billetflow Idler Bracket you will have to add 1/2" to the belt sizes shown below for your application due to its larger size, except where the configuration already notes a Billetflow bracket.

Note that wherever a 75" belt is recommended that the stock 75.1 belt can be used as well.

FYI -- Stock idlers are 90mm. Belts are 8-rib design.

Also note that some of the belts below may no longer be available. I have been informed, for example, that the Gates K080735 is discontinued, and that the K080733 can be used in place of the K080735.

No Idlers

Pulley Size	Belt Size	Gates Micro-V Part #	Gatorback Poly-V Part #
3.65 (stock)	75.1"	K080751	4080750
3.40	75"	K080750	4080750
3.20	74.5"	K080745	4080745
3.10	74.5"	K080745	4080745
3.00	74.5"	K080745	4080745
2.95	74”	K080740	4080740
2.93	74”	K080740	4080740
2.90	74”	K080740	4080740
2.80	73.75”	K080735 (discontinued)	4080735
2.76	73.75”	K080735 (discontinued)	4080735
2.75	73.75”	K080735 (discontinued)	4080735

With 1-Piece Idler (100mm)

Pulley Size	Belt Size	Gates Micro-V Part #	Gatorback Poly-V Part #
3.65 (stock)	75.1”	K080751	4080750
3.40	75"	K080750	4080750
3.20	74.5" or 75"	K080745 or K080750	4080745 or 4080750
3.10	74" or 74.5"	K080740 or K080745	4080740 or 4080745
3.00	74" or 74.5"	K080740 or K080745	4080740 or 4080745
2.95	74” or 74.5"	K080740 or K080745	4080740 or 4080745
2.93	74” or 74.5"	K080740 or K080745	4080740 or 4080745
2.90	74" or 74.5"	K080740 or K080745	4080740 or 4080745
2.80	74"	K080740	4080740
2.76	74"	K080740	4080740
2.75	74"	K080740	4080740

With 3-Piece Idler Set (1-92mm and 2-100mm)

Pulley Size	Belt Size	Gates Micro-V Part #	Gatorback Poly-V Part #
3.65 (stock)	75.1”	K080751	4080750
3.40	75”	K080750	4080750
3.20	75”	K080750	4080750
3.10	75”	K080750	4080750
3.00	75”	K080750	4080750
2.93	74.5” or 75"	K080745 or K080750	4080745 or 4080750
2.90	74.5” or 75"	K080745 or K080750	4080745 or 4080750
2.80	74.5"	K080745	4080745
2.76	74” or 74.5"	K080740 or K080745	4080740 or 4080745
2.75	74” or 74.5"	K080740 or K080745	4080740 or 4080745

With 4-Piece Idler Set (1-92mm and 3-100mm)

Pulley Size	Belt Size	Gates Micro-V Part #	Gatorback Poly-V Part #
3.65 (stock)	76.5"	K080765	4080765
3.40	76”	K080760	4080760
3.20	75.5”	K080755	4080755
3.10	75” or 75.5"	K080750 or K080755	4080750 or 4080755
3.00	75”	K080750	4080750
2.93	75"	K080750	4080750
2.90	75"	K080750	4080750
2.80	74.5" or 75"	K080745 or K080750	4080745 or 4080750
2.76	74.5” or 75"	K080745 or K080750	4080745 or 4080750
2.75	74.5” or 75"	K080745 or 4080750	4080745 or 4080750

Miscellaneous Combos with Larger and Stock Lower Pulley

Upper Pulley	Lower Pulley	Idlers	Alternator Pulley	Misc. Parts	Gates Part #	Gatorback Part #
3.65 (stock)	8 lb.	Stock	3.2"	Lower idler in upper position (recommended position)		4080839
3.65 (stock)	6 lb.	1-100mm 1-90mm	Metco 3.5"	90mm idler (3 hole bracket) in hole closest to crank No snub idler bracket	K080806
3.65 (stock)	6 lb.	3-92mm	3.2"	Lower idler in upper position (recommended position)	K080816
3.65 (stock)	6 lb.	3-92mm	3.2"	Lower idler in lower position (see above recommendation)
3.65 (stock)	6 lb.	Stock	3.5"		K080820	4080820
3.65 (stock)	6 lb.	Stock	Stock		K080810
3.65 (stock)	6 lb.	3-92mm	Metco 3.2"		K080806
3.65 (stock)	4 lb.	3-92mm 1-100mm	3.2"	Idler mounted in lower position	K080797
2.3L Whipple 3.00	Stock	3 - 100mm 1 - 92mm	Stock	New style snub idler	K080774
2.3L Whipple 3.50	4 lb.	3 - 100mm 1 - 90mm	3.2"			4080830
Whipple 3.50	4 lb.	3 - 100mm 1 - 92mm	3.2"	92mm idler in upper position New Billetflow idler bracket		4080830
Whipple 3.50	3 lb.	3 - 100mm 1 - 92mm	3.2"	92mm idler in upper position New Billetflow idler bracket		4080820
Kenne Bell 3.50	6 lb.	3 idlers	Stock		K080810	4080810
Whipple 3.50	Stock	Metco stock sized idlers	Stock	Whipple tensioner	K080764 or K080760
Whipple 3.50	Stock	Metco stock sized idlers	Stock	Stock tensioner with tab broken off	K080774
Kenne Bell 3.50	Stock	4 Metco stock sized idlers	Stock		K080755	4080755
Whipple 3.50	Stock	1-100mm	Stock		K080774
Kenne Bell 3.50	6 lb.	1-100mm	3.5"		K080830	4080830
Whipple 3.25	Stock	Metco stock sized idlers	Stock	Stock tensioner with tab broken off	K080765
Whipple 3.5	4 lb.	3-100mm 1- 90mm	3.2"	LFP snub idler bracket	K080816
Whipple 3.25	4 lb.	3-100mm 1-90mm	Stock	Lower idler in upper position Tensioner notched	K080825	4080825
Kenne Bell 3.25	4 lb.	3-100mm 1-90mm	3.5"	Old style snub bracket	K080825	4080825
Kenne Bell 3.25	8 lb.	3-100mm 1-90mm	3.5"	Hermann's S/C spacer	K080830	4080830
3.10	4 lb.	1-100mm	Stock		K080800	4080800
3.10	4 lb.	2-92mm 2-100mm	3.2"	Updated version of Billetflow idler bracket	K080820	4080820
Whipple 3.00	Stock	3-100mm 1-92mm	Stock	Old style snub bracket Stock tensioner with tab broken off ** Belt was very tight which is what the owner wanted.	K080765**
3.10	6 lb.	1-100mm Snub Idler	3.2"		K080816
Whipple 3.00	Stock	Metco stock sized idlers	Stock	Stock tensioner with tab broken off	K080760
Whipple 3.00	4 lb.	3-100mm 1-90mm	3.5"		K080806
3.00	4 lb.	1-100mm 3-90mm	3.2"	Idler in upper position	K080810	4080810
2.93	Stock	3-100mm	Stock		K080740	4080740
2.93	4 lb.	2-90mm 2-100mm	Stock	Idler on Metco bracket in upper position	K080797
2.93	4 lb.	3-100mm 1-92mm	Stock	Updated version of Billetflow idler bracket Lower idler in upper position	K080797
2.93	6 lb.	3-100mm 1-90mm	Stock		K080797
2.93	6 lb.	1- 100mm	3.5"		K080816
2.93	6 lb.	Stock	3.5"		K080825	4080825
2.93	4 lb.	3-100mm 1-90mm	Stock	New Billetflow bracket Lower idler in upper position	K080797
2.93	4 lb.	3-100mm 1-90mm	3.2"	Lower idler in upper position	K080810 or K080816	4080810 or 4080820
2.93	4 lb.	3-100mm 1-92mm	3.2"		K080810	4080810
2.93	4 lb.	Stock	3.5"		K080797	4080772
2.93	4 lb.	1- 100mm	3.2"	Lower idler in lower position Tensioner notched	K080780	4080780
2.93	4 lb.	1- 90mm	3.2"	Lower idler in lower position Tensioner notched	Dayco Poly Cog Gold Label 5080785
2.93	4 lb.	Stock	3.2"	Tensioner notched	K080797 (some have used K080810)
2.93	6 lb.	2-90mm 2-100mm	3.5"	Tensioner notched	K080810	4080810
2.93	2 lb.	1-90mm	Stock			4080760
2.93	2 lb.	3-100mm 1-90mm	Stock	New Billetflow bracket Lower idler in lower position	K080774 or K080780
2.93 or 2.76	Stock	3-100mm 1-90mm	3.2"		K080760	4080760
2.80	Stock	3-100mm 1-90mm	3.5"		K080755 or K080760
2.80	2 lb.	Stock	Stock	Lower idler in lower position	K080760	4080760
2.80	2 lb.	1-90mm	Stock	Lower idler in lower position	K080765	4080765
2.80	4 lb.	One?	Stock		K080774
2.80	4 lb.	1-100mm	3.2"	Lower idler in lower position	K080780	4080780
2.80	4 lb.	2-100mm	Stock	Lower idler in upper position	K080790
2.80	4 lb.	2-100mm	3.2"	Lower idler in upper position	K080806
2.80	4 lb.	3-100mm 1-90mm	Stock	Lower idler in lower position	K080774
2.80	4 lb.	3-100mm 1-90mm	3.5"		K080760 or K080755
2.80	6 lb.	3-100mm 1-90mm	Stock		NAPA 25-080806
2.80	6 lb.	3-100mm 1-92mm	3.2"	New-style Billetflow bracket Lower idler in upper position	K080810
2.76	4 lb.	3-100mm 1-92mm	3.2"	New-style Billetflow bracket Lower idler in upper position	K080806
2.80	4 lb.	3-90mm 1-100mm	3.2"	Lower idler in upper position	K080810
3.10	6 lb.	3-100mm 1-92mm	3.5"		K080825	4080825
2.76	6 lb.	3-100mm 1-92mm	3.5"		K080816HD	4080820
2.76	2 lb.	3-100mm 1-90mm	Stock	Old-style Billetflow bracket	K080780	4080780
2.76	2 lb.	3-100mm 1-90mm	Stock	New-style Billetflow bracket	K080785	4080785
2.76	4 lb.	3-100mm 1-90mm	Stock	Lower idler is lower position	K080780	4080780
2.76	4 lb.	3-100mm 1-90mm	3.2"	Tensioner not notched	K080806
2.76	4 lb.	3-100mm 1-90mm	3.5"	Old-style Billetflow bracket	K080780	4080780
2.76	4 lb.	3-100mm 1-90mm	Stock	Old-style Billetflow bracket	K080790
2.76	4 lb.	Stock	3.2"		K080797	4080772
2.76	Stock	3-100mm 1-92mm	3.2"	Lower idler in upper position Old Billetflow bracket	K080765	4080765
2.75	2 lb.	1-100mm	Stock		K080780	4080780

Gatorback Functional Part Number Gives You The Size Of The Belt

Example - Part No. 4 08 074 5
     1st digit (4) represents a K section Poly V-belt.
     2nd and 3rd digit gives the number of ribs.
     4th, 5th, and 6th digit are the length in inches.
     7th digit is tenth of an inch.
Part number 4080745 would be a K section Poly-V belt, eight ribs wide, with a length of 74 and 5/10 inches.

Goodyear Gatorback 2001 Catalog Reference

Effective Inches	Gatorback Poly-V Part #
72.5	4080725
73.5	4080735
74	4080740
74.5	4080745
75	4080750
76	4080760
77.25	4080772
78	4080780
79.75	4080797
81	4080810
82.5	4080825
83	4080830
83.75	4080839
85.5	4080855

I have received a comment that Gatorback belts are a 1/2" larger than Gates belts with the same last three digits of the part number. I have not been able to confirm this with either Goodyear or Gates.

Gates 8-rib belt numbers in sizes most likely to be used on Mustangs:

1 1/8” (28 mm) Nominal Top Width for all belts listed below
Length Gates Angle
Inches (mm) Part#
-----------------------------------------
75 1/8 (1910) ................. K080745 40°
75 5/8 (1920) ................. K080751 40°
76 (1931)........................ K080755 40°
76 1/2 (1945) ................. K080760 40°
77 7/8 (1980) ................. K080774 40°
78 5/8 (1995) ................. K080780 40°
79 (2008)........................ K080785 40°
80 1/4 (2040) ................. K080797 40°
81 1/8 (2060) ................. K080806 40°
81 5/8 (2057) ................. K080810 40°
82 1/8 (2085) ................. K080816 40°
82 3/8 (2091) ................. K080817 40°
82 5/8 (2100) ................. K080820 40°
83 1/8 (2110) ................. K080825 40°
83 3/4 (2125) ................. K080830 40°
84 3/8 (2145) ................. K080839 40°
86 1/8 (2190) ................. K080855 40°
89 7/8 (2285) ................. K080893 40°
90 3/8 (2295) ................. K080897 40°
90 7/8 (2310) ................. K080903 40°
92 3/4 (2355) ................. K080922 40°
95 3/4 (2430) ................. K080952 40°
97 1/2 (2475) ................. K080968 40°
98 5/8 (2505) ................. K080981 40°
99 5/8 (2530) ................. K080991 40°
100 5/8 (2555) ............... K081000 40°
102 5/8 (2605) ............... K081020 40°
104 (2640)...................... K081035 40°
110 3/4 (2815) ............... K081102 40°
113 (2870)...................... K081124 40°
115 1/8 (2924) ............... K081145 40°
116 1/4 (2950) ............... K081153 40°
118 1/4 (3005) ............... K081177 40°
119 1/2 (3025) ............... K081189 40°
120 1/8 (3050) ............... K081196 40°
121 7/8 (3096) ............... K081213 40°
122 3/4 (3117) ............... K081223 40°
127 (3227)...................... K081265 40°
136 1/2 (3468) ............... K081359 40°
138 1/4 (3512) ............... K081377 40°

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News

Why Is The Shifter noisy?

Actually it isn't the shifter that is noisy. What you hear is transmission gear noise being transmitted through the shifter into the cabin.

The thin, irregular bead of silicon sealer normally used on the bottom of the shifter base doesn't do well as a noise isolator. The only real noise isolator is the thick rubber gasket on the shifter handle. It isolates some transmission gear noise, but not near enough.

My Shifter Gasket Sets are a simple and inexpensive solution! You can reduce this gear noise and enjoy a quieter shifter. My shifter gaskets work with both stock and aftermarket shifters.

All of my shifter gasket sets are now upgraded to the new double thickness 1/16" PLUS Series. The PLUS Series is easier to install due to the added thickness, and provides increased durability.