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| | [[File:Bbc 702 cc.jpg|thumb|Closed chamber,c/n 702 shown]] | | [[File:Bbc 702 cc.jpg|thumb|Closed chamber,c/n 702 shown]] |
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| − | ==Exhaust valve guides==
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| − | {{Note1}}The following is an excerpt from an AERA technical bulletin:
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| − | '''Exhaust Valve Guide Caution On 1965-98 GM Big Block Engines'''
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| − | These engines' valve guides were not intended as a replacement item from GM.
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| − | The guides were located into the head castings after the head was cast and
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| − | the exhaust guide is "water cooled".
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| − | The water-cooled guide also has two different size press fit diameters. Adding additional confusion to the matter, they also switched the location of the larger diameter sometime in 1985.
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| − | To determine which outside diameter guide you have and which direction to
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| − | remove an exhaust valve guide, the following procedure is suggested:
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| − | Drive the guide no more than 0.250" (6.35 mm) toward the valve spring side of
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| − | the head and stop. Then, measure the newly exposed area of the guide
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| − | OD next to the spring pad.
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| − | If the measurement is 0.620" it is the first style guide. To remove this
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| − | style guide, continue driving it toward the valve spring side of the head.
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| − | If the measurement is 0.616" , it is the second style guide. To remove
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| − | this style guide, you must drive it the opposite direction toward the combustion
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| − | chamber side of the head.
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| | ==BBC L29 Vortec heads== | | ==BBC L29 Vortec heads== |
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