67L78 water pump to crank belt

[67L78]

A while back i asked if anyone knew where i could get the center belt on my three groove cast crank pulley set up on my power steering 396/375. Ed B. said the 65 to 67 corvette 350 horse used that same set up. My kids got me one for my birthday from Corvette Central part# 30256 that is a repo of the old Chevy #3837810. Today i took on the job to install it and thought i'll just try to slip it on before i take all the fan and water pump assembly off and it went on the pulley with no effort at all. Much to loose, i'm guessing about an inch or so too long maybe a little more.
Ed do you think because i have the deep groove pulleys on my car that is making the difference. Did the Corvette 350 horse cars run the deep groove pulleys like my 375 horse engine? Help me on this one RSR.

Confused but not defeated,

Richard

[plumL78]

The assy. manual shows that belt for the 67 L78. I put one on from quanta. Its a little loose but maybe not like yours .  It doesn't fly off

[67L78]

It might be the belt made a little big but i'm afraid it would throw it soon as i started the engine. I saw the one Quanta had but i figured it would be the same, maybe not.

[bertfam]

To answer your question Richard, yes the 327/350 Corvette engine used deep groove pulleys, so I'm not sure why your belt is too long. I've attached the 1967 and 1968 belt charts from the Corvette P&A and it shows the 3837810 belt being used for that engine. And like Kerry said, that same belt is listed in the 67 Camaro AIM for the L78.

The overall length of that belt is supposed to be 3/8" x 34-3/8" so you might want to measure yours. Maybe you just got a bad one?

Ed

[bertfam]

Update. I just did a little research on that belt and apparently there are two different lengths used for that part number!! Read THIS for more info (epecially reply #5 from our own JohnZ).

Perhaps you got the 34.8" belt instead of the 34.4".

Ed

[tmodel66]

It's a little off topic but what purpose does the captive belt serve?

[JohnZ]

It's a little off topic but what purpose does the captive belt serve?

It's a backup so you still have a functional water pump if you throw the fan belt.

[67L78]

Thanks all, I'll look at this belt more closely and figure out its lenght and let you know.

Richard

[67L78]

Measured my belt and i come up with 34 and 7/8 inch. I'm measuring the outside dimension. So i must have the long one.

Thanks all,
Richard

[rsr]

 I've had Quanta belts on 69 L 78s with same part number but vary in length..some tighter than others.Rich  I'm real confused because a 67 L78 chevelle has different pulleys and I haven't found them yet....... so I'll get back to you with belt lenght......hopefully this year?? Thanks