1969 350/350 Exhaust Manifold Bolt Head Markings
Doing a frame off on a 350/350. I have installed the blue printed engine on the rolling frame and am going through the NCRS Manual and have a question about the head marks on the bolts for the Exhaust Manifolds. The head marks on the bolts that came off the car were a mixture of a circle within a circle, an A inside a circle and a N inside a circle. The Manual states that all the bolts have a circle within a circle. Have others encountered this situation with mixed head markings or are all the bolts a circle within a circle? Thanks for any information. Steve
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Re: 1969 350/350 Exhaust Manifold Bolt Head Markings
Steve------
The circle within a circle is the correct headmarking for virtually all small block exhaust manifold bolts. However, there are 2 different length bolts used. It's quite common for different length bolts to have different manufacturer's ID marks. I think you will find that all of the "A" marked bolts are of one length and all of the "N" marked bolts of the other length. Even if this is not the case, different headmarkings can sometimes be found for the exact same bolt size/application on the same car. The bolts were poured into bins (or, drawn from boxes) on racks beside the assembly line. Bolts sourced from different manufacturers (with different ID marks) could easily be mixed. I can assure you that line workers made no effort to ensure that every car got a "matched set".In Appreciation of John Hinckley
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