curved neck 4 core radiator question

[black69]

I am now confused on the aspect of the radiator in my car vs one I just saw with 5k miles on it at MCACN.  Both cars are black (not related to the question) but that is why I looked at the car vs mine.  Both are L78 4:10 cars. One is a M22 and mine is a M21. I forgot all the rules were now on getting a 4 core, and now wonder if a curved neck was part of it.  The 5k mile care built second month has standard neck (considered an early car?), mine made 6C (or D) is curved and is quite patina'd.  would like to know are both correct? did the curve neck version radiator come out later?  I know COPO cars had them.  Just wondering if I got the correct radiator now. Original owner said it was never changed out.

-bob

[x66 714]

I would say both are correct. I believe the curved neck was originally made for BB a/c cars, The hose won't clear the a/c clutch w/o it. It had to do with posi trac axle, 3.73 & 4.10 gears. Included HD cooling in the Apr 1st 1969 order sheets. There was a time frame which is why some had curved neck radiators. William knows more of the details. Guy Youngdell's 375hp has 3.73 posi. His car was built 04C I think. It has the 4 row curved neck radiator....Joe

[bertfam]

Read THIS.

Addition of AC to 1969 big-block engines increased the number of radiator core rows from 3 to 4 and added a curved inlet neck in order clear the 1969 AC components. 1969 COPO 427's (see CRG COPO Research Report) also used this same curved-neck 396/AC 4-row core radiator - eliminating the need for the assembly plant to stock a straight-neck 4-core in 69.

Ed

[black69]

Thanks Joe and Ed,

I like this one statement that was in that last item from info on this topic from CRG:

eliminating the need for the assembly plant to stock a straight-neck 4-core in 69.

I think considering my car was getting late(r) in the normal production cycle (end of June), maybe by then they were just making L78s with the curved neck.   Good to hear its atleast not incorrect as Ed stated.

so why did they put curved necks in COPOs in the first place? Were they all built later in the year? Did they flow better (I doubt it)? Last questions from me for a while, I promise.

-bob

[william]

Early production L78s had ZD 3-core radiators regardless of axle ratio. I have heard that some were built with 4-core radiators, n/c.

As of the April 1, 1969 ordering information, ordering a 3.73 or 4.10 positraction axle with a 396 engine [doesn't state which] now included HD cooling and an MSRP of $56.90. Also states that posi w/Z28 or 396 engine [?] MSRP is $42.15. Difference is $14.75, the MSRP of V01, HD radiator.

The car at MCACN [N604699] had a 3-core based on the Body Broadcast Copy [ZD] but the window sticker lists the MSRP for G80 as $56.90. The car was built on or about February 26, long before the ordering info was changed. Charged for the 4-core, didn't get it.

I have docs for three L78 converts built in May. Two have 3.73 axles and list $56.90 for posi. The other one has a 3.55 axle and lists $42.15 for posi. Maybe it took some time to get it straight.

COPOs 9560 & 9561 included HD cooling and virtually all have the curved-neck 4 core radiator. But not all. Several L72s and one ZL-1 are known to have straight-neck radiators. 1968 BB 4-core radiators had a straight neck and it is possible left-over service inventory was used. Codes were UY & UZ, same as 1969. COPOs built prior to June do not list Positration or the standard axle ratio on docs. Starting late in June, many list both with the $56.90 charge for posi. But not all of them.

[black69]

Thanks William,

That was a good read.  No doubt things can change during a production cycle, especially on this topic.

I went back and re-read all the info again on CRG and none of this is there as you described (non AC 396).  At a minimum the table for 69 is wrong (it can be 3 or 4 row) depending on an ordering option of something else (axle related) or when the car was made in the production cycle.  Unless I missed a footnote that is.

I bow in your direction
-bob

[Sauron327]

No such thing as a 2,3 or 4 core radiator. Radiator cores consist of rows. Never understand why gearheads cannot get this right. I can only imagine how people are installing a four core radiator in their car. That is huge.

[william]

so why did they put curved necks in COPOs in the first place? Were they all built later in the year? Did they flow better (I doubt it)? Last questions from me for a while, I promise.

First two ZL-1s [Dec '68] had 4-core radiators.

High compression, low rear axle ratio adds up to a lot of engine heat at low vehicle speed. Throw in a hot day and a 3-core was probably marginal.

Always an engineering reason for changes like these.

[Sauron327]

Wow. Cannot believe the experts on this site do not know a radiator core consists of rows. So let me get this straight... I can take four radiators with 4 with four rows in each core, strap them together and have what? That is one big a$$ radiator.

Doubtful most on this site have radiator experience. I thought CRG members were gods.

[william]

As long as I have been in the hobby, it has been a convention to refer to a radiator by the number of rows of tubes the core contains. A '4-core' radiator has 4 rows of tubes in its core. Everyone understands that except you. Some guys say wheels, some say rims. Same deal.

Quoting Thumper: If you can't say nuffin' nice, don't say nuffin' at all.

[bcmiller]

Nobody is a god except god. C’mon let’s try to be civil. Minor wording differences aren’t worth squabbling over.

And what Bill said is right on. My 11:1 454 bored 0.060 over with 3 rows tends to run on the hot side on days over 90F. I probably should be running a radiator with 4.

[MO]

Agree, my 67 L78  with a 3-row radiator would only run cool (at least to my satisfaction) when it was cruising on the highway. I removed it and installed a 4-core and never had a cooling issue again. Row or core, radiators have been referred to by those terms from day one I imagine. Everyone knows what you're talking about no matter which term you use.

[Sauron327]

As long as I have been in the hobby, it has been a convention to refer to a radiator by the number of rows of tubes the core contains. A '4-core' radiator has 4 rows of tubes in its core. Everyone understands that except you. Some guys say wheels, some say rims. Same deal.

Quoting Thumper: If you can't say nuffin' nice, don't say nuffin' at all.

I get it and your statement is contradictory within two sentences. I'll send you a set of tanks and let me k\now how you fit 16 rows in it. Civil? We had a radiator shop in our old bodyshop and not once do I recall calling a supplier ordering a four core replacement. I'm not the only shop who is perplexed by this. Big difference between rims and wheels and the tires that are installed on them. Same as referrring to value as color in the art field. Surely I'm not the only on who paints and welds nearly everyday. I'm only 56 and surely do not consider myself a god. Good luck boys.

[bcmiller]

Not sure what has gotten under your skin.

You have been a very valuable resource - and I hope you can continue on that route.

But there seems to be a chip on your shoulder. Let’s all try to get along.

[william]

I get it and your statement is contradictory within two sentences. I'll send you a set of tanks and let me k\now how you fit 16 rows in it. Civil? We had a radiator shop in our old bodyshop and not once do I recall calling a supplier ordering a four core replacement. I'm not the only shop who is perplexed by this. Big difference between rims and wheels and the tires that are installed on them. Same as referrring to value as color in the art field. Surely I'm not the only on who paints and welds nearly everyday. I'm only 56 and surely do not consider myself a god. Good luck boys.