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- - bolt size/thread for crankshaft snout? (https://67-72chevytrucks.com/vboard/showthread.php?t=517751)

flyngti

04-03-2012 12:24 AM

bolt size/thread for crankshaft snout?

I'm finishing up my rebuild for the War Wagon. The motor is the original 307 V8. On teardown, I noticed the harmonic balancer bolt was missing and the threads look a little munged up. Anyone know what is the correct size and thread pitch for a 1969 307 crankshaft? I need to get a new bolt and probably need to run a tap to clean up the threads.
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Lee H

04-03-2012 12:18 PM

Re: bolt size/thread for crankshaft snout?

GM used two sizes for the small blocks, 7/16-20 and 3/4-16. All mine have been 7/16-20.

flyngti

04-03-2012 07:53 PM

Re: bolt size/thread for crankshaft snout?

Thanks Lee. I should have searched before I posted, but it sounds like many (all?) 307 and 327 motors do not have a harmonic balancer bolt!

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