More 3810 and 3367 Holley questions

[Bob S.]

Re: More 3810 and 3367 Holley questions

Jerry - Which Holley publication(s) contain(s) the carb parts and parts comparison sheets you posted a couple of weeks ago? Was it the Holley Illustrated Parts and Specs Book? 'Can't tell from the website or talking to them...

Thanks,
Bob

[Gerard F.]

Re: More 3810 and 3367 Holley questions

Bob,

That's the Holley pub I have, Illustratrated Parts and Specs.

My version is Part No. 36-51-7.

Got it in 2004 from the Holley website, and it was supposed to be the latest version at that time.

[John H.]

Re: More 3810 and 3367 Holley questions

There's evidence from John Hinkley that at least some 3810's left the factory with the baseplate stamp, so it would be interesting to see if anyone has a known original 3810 not having it. Bob

Bob - Maybe you're thinking of someone else - I haven't researched the 3810 baseplate stamping issue. Where on the baseplate have you noted the stamping?

[Gene M.]

Re: More 3810 and 3367 Holley questions

I just went down to the garage to check my silver '67 coupe's 3810 carb. I'm 3rd owner of car and know it to be original to car and there is no number stamping on the base foot.

I have one question. First, I'm seeing unrestored Holley carbs both here and on the show field that appear greenish in carb castings with silver (clear zinc) stampings and linkage. And that is the way I remember them back in the 60's. Why are "restored" Holleys being presented in gold finishes and nobody is saying anything about it? I lived thru the 60's and Holleys were NEVER beautiful gold in color. Grab greenish, pukish yellow were the norm but never gold. Also the sheet metal linkage was a silverish metal color or zinc to a possible rainbow yellow chromate. Again not gold. What gives?

[Gerard F.]

Re: More 3810 and 3367 Holley questions

John,

I think Bob is talking about this, as the location of the stamping:



If you look close at the 3810 stamping, you'll notice that it is stamped twice, like the stamper screwed up the first time.

Would be great if you could research Bob's question.

[Gerard F.]

Re: More 3810 and 3367 Holley questions

Gene,

You're right. If you are restoring your baby at home, or in a small shop, one tends to over-restore and go for a nice even finish. If you are doing one carb at a time, with the same coloring mix over a short period of time you will probably get that, and with a lot of trial and error. 4 times on my carb body until I was happy with it.

But if you consider the original carbs, finished in parts at different factories, and at different times, and on a mass production schedule, one could probably have six different shades of finishes and quality just on the potmetal parts. Also considering the variability of potmetal itself, the take of the dichromate on the potmetal could have yellow, gold, brass, green, and red tints.

However, I think the predominant color on the 66-67 Holleys was an irridescent light gold finish on the potmetal. This finish darkens and dulls with age under the engine heat. I've seen potmetal replacement parts coming out of the box looking more green to me than gold, just depends what particular mix and temperature, they were colored with.

So I think there is a lot of variability in the original Holley carbs in finish on the potmetal parts. On the zinc plated dichromate colored steel parts, it depends just how fast you want to do it, and there's also a lot of variability there and in the years. The steel parts on home restoration are also probably over-restored.

[Gene M.]

Re: More 3810 and 3367 Holley questions

Jerry,
I must complement you, very nice job on your Holley, very realistic greenish hue. A while back you posted some nice photos. And it didn't look over restored.

But my point is that in NCRS restoration we should attempt to restore Holley carbs as they looked when new, not as best we can make them. If you observe unrestored Holley castings the coloring is not gold looking at all. Its more pale greenish to yellowish hue.

Compare side by side an unrestored unit with one of the "gold things" that come out of restoration businesses. It just upsets me that this very obvious incorrect coloring has become an accepted way of life in NCRS. Nobody attempts to vary colorings of the different pieces (bowls, main body, choke mount, etc) on any one carburetor to look authenic. The chromate coatings are applied too much and way to dense. The finished assembly appears as if it was one piece because the coloring is so thickly applied and so uniform as if painted. We strive to have other things so correct (such as raw castings on exhaust manifolds and rag joints with bare steel half shafts) and just over look the carburetor finishes.

[Gerard F.]

Re: More 3810 and 3367 Holley questions

Gene,

The trick I learned with potmetal is to not plate the part with zinc. Just bring it down to a clean fresh zinc finish prior to the chromate dip. That's the way they did in the original production. This will bring out the coloring of the impurities in the base metal.

Also the length of the dip should be fairly short, less than 30 seconds depending upon the concentration of the chromate dip. If it is too short, you don't get full coverage, too long it gets too dark. That's where the trial and error enters, if you are only doing one carb. In production they just had a set time for the group of carb parts being finished, and really didn't care how even things came out.

If you plate the potmetal with zinc, it then comes out shiny gold looking, with too long a dip, brassy. I think that is what you are seeing with the restored carbs.

As for the steel parts, they were intended to be the yellow shiny finish over zinc plating. Too long a dip, turns this into the duller gold or brassy finish.

[Bob S.]

Re: More 3810 and 3367 Holley questions

Bob - Maybe you're thinking of someone else - I haven't researched the 3810 baseplate stamping issue. Where on the baseplate have you noted the stamping?

John - I'm sorry! Thanks for your correction.....your reply was on the 3367 throttle lever and had nothing to do with the baseplate stamping.

So far, it looks like Gene's the first to weigh in on the basplate stamping. .....in his case for the 3810.

I mis-remembered your post as a result of trying to accomplish too much in too little time....

Bob

[Brian M.]

Re: More 3810 and 3367 Holley questions

No stamping of 3810 on my not known to be original base plate.