MODIFYING THE   BOLT PATTERN
 

 

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 Now it's time to fix the bolt pattern. The four corner holes are correct, all the rest are wrong. I first filled all the wrong holes with JB Weld, and sanded smooth when dry. Then I bought stock standard V-8 gaskets to locate my new holes. I have 1986 and prior heads so my middle two holes on each side will be on an angle. If you have '87+ heads your center two holes will be straight up. I hand drilled with no guide, basically guessed at the angles. I had lots of filing to do when I put the intake on the engine due to minor errors on the hole angles.

 

 

 

 

Marking and drilling the holes.

 

 

 

 

Finished, or so I thought. I had lots of filing to do for final fit. I used washers under the intake bolts to ensure a good grip.

 

 

 

 

 

Some of the holes are close to the plenum so allen head intake bolts were needed.

 

 

 

 

 

Look closer at these two center holes. I had to grind lots into the casting to get the bolts to start because of the angle of pre '87 heads. You late model guy/gals won't have this problem.

 

 

 

 

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