A modification that you can do if you have the pipe out is at the last "elbow" install a "cleanout" on the heel of the 90 that you can extend out from underneath the intake manifold and have some type of screw cap on it (I envision using a SwageLock cap for this). Anyway, whenever you get the pluggage code all you would have to do is remove the cap and rod out the straight section from the intake manifold side. This mod will take a skilled hand at "tubing" type work - cutting/shaping/brazing/welding.

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Jim