Need Help With Belt Size (Changed My Alternator - Aftermarket)

[KingCobra03SVT]

My alternator went in my Cobra so I bought a PA Performance 03-04 Cobra 130 Amp Alternator.

http://www.lethalperformance.com/pa...rformance-03-04-cobra-130-amp-alternator.html

I noticed that the pulley is bigger on this alternator than the stock unit. Now I need a new belt. The alternator is already in the car right now and tightened down. I just need to put the belt on.

I had the Gatorback Goodyear belt 74.5 (4080745)

Which one do I need now? :shrug:

Does anyone have this alternator with a 2.76 upper only? If so what belt size did you use? Thank you

Here is the list from Cobrabob's site that I found of the Gatorback Goodyear sizes.

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

 

[KingCobra03SVT]

Here are some photos:

NEW ALTERNATOR

I THINK THIS PICTURE DEPICTS HOW MUCH BIGGER IT IS THAN THE STOCK UNIT

I THINK THIS IS A CLOSE REPRESENTATION OF HOW MUCH BIGGER THE NEW ALTERNATOR PULLEY IS.

 

[KingCobra03SVT]

Well I Figured This Out On My Own. I Took A Thick Piece Of String/rope That Resembles The Belt Thickness And I Tied It Around All Of The Idlers, Tensioner, Alternator & Blower Pulley.

I Then Pulled The Rope/string Very Tight And Marked Where The End Of The String And Other End Of The String Met Together. I Then Layed The Rope Out On My Kitchen Floor Which Has Vertical And Diagonal Lines In It And I Lined The Rope Up Perfectly With The Vertical Lines.

I Then Had Someone Step On The End Of The Rope So I Could Pull It Tight. Then I Took A Tape Measure And Measured From The End Of The Rope To The Mark I Had Made. I Had Someone Put Their Foot On Both The Rope And Tape Measure To Keep The Measurement Accurate And Tight.

I Came Up With A Measurement Of Exactly 77.25 With My Mark. I then looked at Cobrabobs sight and seen that Goodyear Makes A Belt That Is Exactly 77.25!!! How crazy is that!? So I Am Going With That Since The Next Belt Size Is 78 I Know My Science/math Is Correct/accurate!!