Casting marks on AC Mounting Brackets ??

[Mike B.]

Good Afternoon Joe,

I'm planning on posting a thread on big block air conditioning cast brackets in the future and would like your input here.

My friends and I have an inkling of what these additional casting numbers represent but we're not entirely sure. On the cast iron AC brackets there is a "C" surrounded by a triangle next to the part's casting number. Then there's a "1, 2, or 3" either to the left or right of the triangle. See attached photos.

What do these numbers mean? Do they designate early, mid, or later "runs" of these brackets from the foundry?

The reason we're curious about this is for possible detective work. For instance, what if there's a survivor car $$$ for sale and the owner says the car's never been touched but you find on this very early car that it has a "3" cast bracket installed? And this bracket was just released into that production year and has never been in production before. Would you be suspect of the bracket's originality to the car?

Some people don't care about small facts as these. But I've always been curious about these marks. You'd be the one who'd know of these markings. Thanks Joe, Mike

[Terry M.]

Re: Another question for Joe Lucia and the Experts

Mike
As you can see I am not Joe Lucia, and I don't regard myself as an expert either. Nonetheless I will offer my 2 cents.

On other castings (cylinder block, cylinder heads, etc) those kinds of numbers represent the mold that the casting was produced in. This allows foundry workers to track any defects back to the source for correction. Castings are produced on rotating machines that may have many molds in them. The numbers have nothing to do with time produced.

I suspect the numbers you see serve the same purpose.

The C in the triangle is the mark of the company producing the brackets, or perhaps the casting plant.

Like you I am eager to see Joe's response.

[Mike B.]

Re: Another question for Joe Lucia and the Experts

Thanks Terry for your response.

I just had a good conversation with another NCRS buddy, Mark Nagy up in Indiana on this subject. Beautiful state-of-the-art resto currently finishing up on his '66 425hp coupe. He agrees with your description. We are using the '66 Corvette production run as the example.

He explained to me that most probably there were multiple lots of these big block air conditioning brackets produced at the foundry for quality control purposes at any given time. Each of them would show their lot control number. Seeing as though there were about 100 cars or so built each day and out of them, one lot may not have been able to keep up with demand. Especially if a defect was found in the current lot brackets.

My initial post here was based on a very early 1966 big block AC compressor I know of with a casting date of early August '65. Both of the very rare cast "66 only" big block compressor brackets for that compressor were both marked with the number "1". This led me to assume that these numbers on the brackets might have had a correlation with time.

Yes Terry, let's both hear what Joe's take on this is. Thanks again for your response.

Mike

[Mark E.]

Re: Another question for Joe Lucia and the Experts

Mike,

I hope you get the information you want.

This thread, and a couple of other recent threads, were titled "Question for Joe", or something similar. I understand the desire for an individual to get a quick answer for their personal question, and that's one purpose for this forum.

Broader, and I argue more important, purposes for this forum are for the rest of us to learn, and as a knowledge base that's searchable using keywords.

"Question for Joe" isn't a common search phrase (although it would probably pull up some interesting reading :-)). So I suggest all of us be mindful about using a descriptive title for our threads.

Alternatively, when there's a question for a specific member, send a PM.

[Mike B.]

Re: Another question for Joe Lucia and the Experts

Point taken Mark,

If folks have read my prior posts then they would know how inclusive I am of everybody's input. I did use the words "and the experts". Meaning anyone who'd care to shed any expertise they might have to the post.

But guilty as charged. I'll select a more general title next time so as to not offend anyone out there.

Mike

[Don H.]

Re: Another question for Joe Lucia and the Experts

I retitled the thread.

ps.
It's never any problem at all to make a correction to a thread title, or write a new title so do not hesitate to drop a note and ask me.
I'm happy to do it.

[Mike B.]

Re: Casting marks on AC Mounting Brackets ??

Thanks Don,

I was going to contact you of how I could re-title my threads. Sorry for any inconvenience.

Always a pleasure,

Mike

[Kenneth B.]

Re: Casting marks on AC Mounting Brackets ??

As Terry said those are impression #'S. I assume there were 3 impressions in each mold which would produce a 1 2 3 casting per mold so there would be NO correlation to the #"S and dates.

[Mike B.]

Re: Casting marks on AC Mounting Brackets ??

Thanks Kenneth and Terry,

Looks like those very early brackets with the #1 stamps led me to the wrong assumption of a correlation with time. Thanks for your inputs.

Mike