My 70 442 AC belt is squeaking. Looked up a Gates replacement at Oreillys today - guy says it is supposed to be about 58" long but mine measures almost 64". What is the correct length belt? Who knows I might have the wrong pulleys...

 

The factory belt is P/N 401475, which is a 60.5" belt according to the parts book.

 

What's odd is the existing belt (not broken and works fine) measures exactly 63- 5/8" outside. No way a belt 3" shorter is going to fit.
could it be I have an incorrect pulley on crank?

 

Seems I remember the belt is supposed to be measured differently than that.

 

Correct. The outer circumference is not the published measurement. Depending on the cross section of the belt, you subtract 2"-3" from the outer circumference to get the rated length. 63 5/8 - 3 = just about exactly the 60.5 the factory says it is. Keep in mind that there is more than 1" of travel in the adjusting slots, and a 1" longer belt amounts to only about 1/2" extra travel in the adjusting slot.

 

By the way, this is why I have one of these:

 

10-4 I found an Oreillys with the right belt - will go get tomorrow and see how it fits

 

Got the Gates 7603 belt which is advertised as 60 13/16 long and correct for a 70 442 - not even close to fitting. Way too short.

 

All I know is what the factory says. How about a photo of your bracket setup and pulleys.

 

Gates lists 7603 as the correct number if you look it up by make and model but if you look it up the cross reference to the gm number 401475 it comes up 7612.
per gates web site 7603 has an effective length of 60 inches , the 7612 has an effective length of 61 inches.
how much to short is the 7603?

 

 

Same info as shown in Post #2.

 

Pics attached. Crank pulley and WP pulley are both 3 groove and all 3 the same size. Second to last pic compares new belt to the old

 

The picture I posted has the pulley codes , see if you have the correct set of pulleys
KC for the crank
KF for the water pump
KH for the power steering

 

Got the Gates 7630 and it fit great. This is significantly longer than the 7603.