Belt Number often is off to actual length.
many say this in many catalogs etc. because can't make total exact match for each batch of belts.
Is Why most OE Tensioners have a "Window" to accept a belt bit loose or tight. And why many adding tensoiners as aftermarket "kits" often have problems and not just this.
Do Not Force a tensioner to take a belt.
Many will hate you and fail because hits limit at "top" of Range of Motion w/ a Short belt. OE tensioner for 87-88 Fiero 4 cyl isn't only one that can break when have a short belt. See my Cave,
Serpent BeltWorse, many alt etc have been replace and pulley may not be exact same as OE pulley. Small different in pulley diam can change belt length needed when you can't adjust the alt or whatever.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)The Ogre's Fiero Cave[This message has been edited by theogre (edited 05-28-2022).]