Editing Intake manifold
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From 1955 until about 1986, all SBC engines had the same 12-bolt intake bolt pattern. In about 1987, GM changed the center 4 bolts to 72 degrees. This was used (except on Corvette aluminum heads, which retained the early bolt pattern) until the 8-bolt Vortec head bolt pattern took over in about 1996. | From 1955 until about 1986, all SBC engines had the same 12-bolt intake bolt pattern. In about 1987, GM changed the center 4 bolts to 72 degrees. This was used (except on Corvette aluminum heads, which retained the early bolt pattern) until the 8-bolt Vortec head bolt pattern took over in about 1996. | ||
− | The early intake can be made to fit later 72 degree heads by slotting the bolt holes and fabricating (or buying) shims to correct the angles | + | The early intake can be made to fit later 72 degree heads by slotting the bolt holes and fabricating (or buying) shims to correct the angles. [http://www.persh.org/pickup/TBI%20Intake%20Manifold.htm '''Using a stock TBI Intake Manifold'''] and [http://www.hotrodders.com/forum/sbc-87-cast-iron-heads-vs-older-intake-55-86-a-175547.html#post1250079 '''this Hotrodders forum thread'''] has the details. |
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+ | Neither of the earlier intake bolt patterns are compatible with the Vortec 8-bolt cylinder head, nor can a Voterc intake be used on either of the earlier bolt pattern heads. | ||
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==Types of intakes== | ==Types of intakes== | ||
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*[http://www.hotrodders.com/forum/carb-spacer-163755.html Carb spacer] thread on Hotrodders forum. | *[http://www.hotrodders.com/forum/carb-spacer-163755.html Carb spacer] thread on Hotrodders forum. | ||
*[http://cms.nhra.com/dragster/1999/issue05/racing_technology.html Racing Technology Tuning with carburetor spacers] from NHRA.com | *[http://cms.nhra.com/dragster/1999/issue05/racing_technology.html Racing Technology Tuning with carburetor spacers] from NHRA.com | ||
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==Marine intakes== | ==Marine intakes== | ||
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[[File:VORTEC INTAKE BOLTS.jpg|thumb|left|]] <br style="clear:both"/> | [[File:VORTEC INTAKE BOLTS.jpg|thumb|left|]] <br style="clear:both"/> | ||
− | ==Using early intake on later (non Vortec) heads== | + | ===Using early intake on later (non Vortec) heads=== |
On the 1986-back heads and intakes, the center four bolts were the same angle as the other bolts. 1987-up use a different 72 degree angle except for Corvette aluminum heads. To compensate, spacer/washers can be made or [http://www.holley.com/90748.asp '''bought'''] to allow the intake to fit. | On the 1986-back heads and intakes, the center four bolts were the same angle as the other bolts. 1987-up use a different 72 degree angle except for Corvette aluminum heads. To compensate, spacer/washers can be made or [http://www.holley.com/90748.asp '''bought'''] to allow the intake to fit. | ||