I have a mix of flange bolts on my intake. Many are the circle A head mark (grade 5) and some have a "CP" head mark (also grade 5). I cannot find reference in the archives to the CP mark as being used but I am rather sure the engine was never taken apart before restoration. I trusted the engine rebuild to a mechanic so I don't know if he changed out bolts. So, was CP an acceptable mark?The two bolts for the lift eye were wrong so I put TR bolts in them. However, I used a bolt and lock washer. Was this wrong and should I find some flange bolts?thanks
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Re: 1968 427/390 intake manifold bolt questions
Russ------
It's very possible that different headmarking manifold bolts were originally used on the same engine. However, usually, you will find that the different bolts will be of different lengths and/or different head configuration (e.g. standard hex head versus flanged hex head).
The bolts which also retained other brackets (e.g. lift brackets, distributor shield supports, etc.) were usually slightly longer than the bolts used for non-bracket positions. The headmarking of the longer bolts was almost always different than the non-bracket-retaining bolts.
"A" and "CP" are common headmarkings seen for big block manifold bolts. Any position which originally used a lockwasher did not originally use a flanged head bolt.In Appreciation of John Hinckley
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