1966 427 fan questions...

[Steven S.]

I'm looking to be armed with info to begin my search for a fan, so what can you guys tell me about the correct fan for a '66 L72? I've read the info from Noland's Vol.2, and what the TIM&JG had to say (which seem to conflict), and I have a few pics of alleged originals, but I would like know more about the stampings, from what I understand, a correct fan would have "FRONT", "H", "66", and possibly "W" stampings, is this correct? What if there was only a "6"? Service replacement? Are there any current dimensionally correct blades still available through GM? How are the repos?

Thanks in advance,
Steve

[Joe L.]

Re: 1966 427 fan questions...

I'm looking to be armed with info to begin my search for a fan, so what can you guys tell me about the correct fan for a '66 L72? I've read the info from Noland's Vol.2, and what the TIM&JG had to say (which seem to conflict), and I have a few pics of alleged originals, but I would like know more about the stampings, from what I understand, a correct fan would have "FRONT", "H", "66", and possibly "W" stampings, is this correct? What if there was only a "6"? Service replacement? Are there any current dimensionally correct blades still available through GM? How are the repos?

Thanks in advance,
Steve

Steve-----


Every example I have seen of the GM #3888366 fan blade assembly has had the "FRONT", "H", and "66" stamped on it. I think there was a "W" on them as well, but my recollection is fuzzy on that point. They have NO stampings on the blades. This description includes both PRODUCTION and NOS SERVICE examples (I have several of both; none for sale).

Were there any manufactured with only a "6" instead of "66". Well, the "66" was not a requirement made in the GM specifications for the part. Presumably, that was something the manufacturer added to enable their identification of the fan blade assembly or, at least, the spider section. However, if a single "6" was used, I don't think it had anything to do with whether the fan was of PRODUCTION or SERVICE origin. Much more likely it was just an "aberation" that occurred at some time during the period of time this part was manufactured. This fan was only manufactured for a period of about 5 years.

There are NO configurationally correct fan blade assemblies currently available from GM and there hasn't been for about 35 years.

[Steven S.]

Re: 1966 427 fan questions...

Thanks Joe, I was hoping you would chime in!

Steve

[Wayne M.]

Re: 1966 427 fan questions...

.... I've read the info from Noland's Vol.2, and what the TIM&JG had to say (which seem to conflict), and I have a few pics of alleged originals, but I would like know more about the stampings, from what I understand, a correct fan would have "FRONT", "H", "66", and possibly "W" stampings, is this correct? Steve

Steve -- you may have already seen these pics of my original. Noland's Vol 2 GM blueprint on pg. 415 indicates 17_1/2 inch diameter (but mine is closer to 17.0"). I'm almost certain the "66" is the last 2 digits of the 3888366 part #. The "W" is on the backside spider.

Sorry, I can't help more than that.

[D S.]

Re: 1966 427 fan questions...

Would this same blade also be used in '66 396/427 passenger car applications? With AC?

Thanks,
Scott

[Steven S.]

Re: 1966 427 fan questions...

Thank you Wayne, I did not have those pics, and those are some good shots! I'll use them for reference.

I too am wondering if this fan was Corvette only, or if there were other applications.

Steve

[Joe L.]

Re: 1966 427 fan questions...

Would this same blade also be used in '66 396/427 passenger car applications? With AC?

Thanks,
Scott

Scott and Steve-----


No, the GM #3888366 was a Corvette-only fan blade assembly and used only for some 1966-70 applications.

[Steven S.]

Re: 1966 427 fan questions...

Joe, is there a current clutch available through GM that would work correctly with this blade??

Thanks,
Steve

[Joe L.]

Re: 1966 427 fan questions...

Joe, is there a current clutch available through GM that would work correctly with this blade??

Thanks,
Steve

Steve-----


Definitely. In fact, it's very close in configuration to some of the originals used in 1968-70 period. It's GM #3916141 and that part number dates back to 1968, although there have been minor changes in configuration since then.

This is the ONLY fan clutch still available from GM for ANY 1960-70 Corvette application and, if one is maintaining the 1960-70 configuration, it's the ONLY one I recommend for FUNCTIONAL reasons as well as configuration (remember, functionality ALWAYS trumps configuration but in this case you get both).

The problem is that this Eaton-manufactured clutch currently GM lists for about 260 bucks. However, you can find brand new examples on eBay for quite a bit less than that.

[Steven S.]

Re: 1966 427 fan questions...

Sounds good

[Curt C.]

Re: 1966 427 fan questions...

In fact it is available on gmpartsdirect.com for $154.20.

[Steven S.]

Re: 1966 427 fan questions...

Let me ask this, what about AC Delco #1582075?? Isn't #3916141 made by Eaton for AC Delco??

[Joe L.]

Re: 1966 427 fan questions...

Let me ask this, what about AC Delco #1582075?? Isn't #3916141 made by Eaton for AC Delco??

Steven-----

GM #3916141 is an Eaton-manufactured fan clutch. However, as far as I can tell and am aware, it's available only through the GM parts system. It's not an AC Delco-available part. I believe that some large Delco parts distributors are able to obtain this clutch directly from Eaton and sell it at a lower price than that obtainable through the GM parts system. It's the same piece, but it doesn't come in a box with a GM part label or part number.

I can't find any record of AC Delco #1582075. I expect the actual number is 15-82075 but I can't find that one, either. It may be a very recent addition. However, I can tell you that most of these AC Delco fan clutches are aftermarket-type, "el-cheapo" clutches manufactured by Hayden, Airtemp, etc. Many are non-thermal type clutches which are the "low budget" pieces. These clutches are configured completely different than original units, can be so-discerned at a glance, and do not perform anywhere near as well as PRODUCTION-type pieces (i.e. like the 3916141).There are some PRODUCTION-type clutches available through Delco for 1971-82 Corvettes, but there are none for 1970 and older applications.

[Steven S.]

Re: 1966 427 fan questions...

I see... the reason I had mentioned that Delco unit is it came up when I was searching through a parts houses listings for the vehicle, it was almost half the price of the GM unit from ebay, and I was curious if perhaps it was the same piece under a Delco number.

So how does the relationship between AC Delco and GM work? I guess I always thought AC Delco parts were basically genuine GM parts.

Thanks,
Steve

[Joe L.]

Re: 1966 427 fan questions...

I see... the reason I had mentioned that Delco unit is it came up when I was searching through a parts houses listings for the vehicle, it was almost half the price of the GM unit from ebay, and I was curious if perhaps it was the same piece under a Delco number.

So how does the relationship between AC Delco and GM work? I guess I always thought AC Delco parts were basically genuine GM parts.

Thanks,
Steve

Steve-----

GM has, essentially, TWO parts systems (actually, several more but we don't need to get into those here). The GM parts system sells primarily PRODUCTION-type parts. These are all sold under a GM part number. The GM part number is usually always preceded by "GM" and is 5 to 8 digits in length (with most parts still available today in the 7 or 8 digit range). This part number is known in the vernacular as the "long number". There are no "dashes" or alpha characters used in a GM part number. GM part system parts are sold ONLY through franchised GM new car dealers. Any price competition that exists, exists only from one dealer to another.

The Delco part system is different. It is GM's parts channel for, essentially, AFTERMARKET-type parts. The Delco parts system sells into a HIGHLY competitive market with all sorts of "players". The cost of the parts has to be kept down if AC-Delco is to be competitive in the aftermarket.

Sometimes, the parts sold by AC Delco are EXACTLY the same as those sold through the GM parts system; sometimes they are not. The case of the 60-70 fan clutch is a perfect example of the latter. The clutch sold through the GM parts system is different than that sold through the Delco parts system. Likely, at some point, Delco made the decision that the Eaton manufactured clutch sold through the GM parts system and a PRODUCTION-quality piece was too expensive for the Delco parts system. In other words, if they offered it at the price they would have to charge (even if that price was lower than through the GM parts system), it wouldn't "sell" in the aftermarket. Most folks would just purchase a competitor's less expensive (and, lower quality) clutch. That's how things work in the aftermarket.

Delco part system parts often have a Delco system part number. This number is different than a GM parts system number. It may contain dashes and alpha characters. This number is known in the vernacular as the "short number". Sometimes, it will be a GM parts system style number but it will be a number that's not carried in the GM parts system. Sometimes BOTH a Delco part number and a GM part number will identify a part.

So, how can you tell, FOR SURE, if a Delco parts system part and a GM parts system part are EXACTLY the same. It's easy. BOTH will have the SAME GM parts system part number on them. The Delco parts system part might also have a "short" number on it. But, if the part available through the GM parts system has the same long number on it as the part sold through the Delco parts system, THEN THE PARTS ARE IDENTICAL. Period. If the long number on the GM part system part and the long number on the Delco parts system part are different, then THE PARTS ARE DIFFERENT. Period.

What if there is no long number on the Delco parts system part? Then, 99.9% of the time, the part will NOT BE THE SAME as the part sold by the GM parts system for the same, exact application.

There's LOTS more to this story but I've written an essay here already and I don't want to extend it into a book.