'69 L36 Intake Manifold Bolt Finish

[Floyd B.]

Amazingly enough I could not find an answer to this question in the archives...

What is the proper finish on the bolt heads of a 427/390 (alum intake) car?

[Brandon T.]

Re: '69 L36 Intake Manifold Bolt Finish

A natural finish

[Joe L.]

Re: '69 L36 Intake Manifold Bolt Finish

Amazingly enough I could not find an answer to this question in the archives...

What is the proper finish on the bolt heads of a 427/390 (alum intake) car?

Floyd------


The bolts on aluminum manifold cars were zinc plated. Cast iron manifold cars may have used black phosphate-finished bolts but it's a fairly moot point since those bolts were painted with the engine.

[Floyd B.]

Re: '69 L36 Intake Manifold Bolt Finish

Joe,

Thanx for the information. Now for the next detail: would you mind providing a "map" of the bolt head markings on the intake bolts on your '69? I haven't been able to form a consensus on which bolt manufacturers would have been typical in '69. e.g. "TR", "FP", none, etc. except that everyone seems to agree that there would have been some "A" mark bolts. It also appears that the "A" marking on current repro's isn't as distinct as it was on originals.

Thanx,

-Floyd-

[Joe L.]

Re: '69 L36 Intake Manifold Bolt Finish

Joe,

Thanx for the information. Now for the next detail: would you mind providing a "map" of the bolt head markings on the intake bolts on your '69? I haven't been able to form a consensus on which bolt manufacturers would have been typical in '69. e.g. "TR", "FP", none, etc. except that everyone seems to agree that there would have been some "A" mark bolts. It also appears that the "A" marking on current repro's isn't as distinct as it was on originals.

Thanx,

-Floyd-

Floyd-----


My 1969 is not an original big block so I can't offer any empirical information here. I never really studied the intake bolt headmarkings on other original 1969 big blocks so I can't help from that vantage either.

[Floyd B.]

Re: '69 L36 Intake Manifold Bolt Finish

Any opinions on whether I would take a deduction if restored original bolts are cad plated rather than zinc? I realize this depends on the judge and his knowledge of faster finish/appearance but what would expect to happen in most cases?

[Joe L.]

Re: '69 L36 Intake Manifold Bolt Finish

Any opinions on whether I would take a deduction if restored original bolts are cad plated rather than zinc? I realize this depends on the judge and his knowledge of faster finish/appearance but what would expect to happen in most cases?

Floyd------


I doubt there is a judge that could make a definitive judgement regarding whether a part is plated with zinc or cadmium. There are some that might THINK they can tell the difference but I really doubt they can. Some think that if the finish is "dull" appearing, it's cadmium and if it's bright, it's zinc. That's nonsense. Either finish can be dull or bright depending upon factors other than the plating material.