CJ or 4V

[Topless73Qcode4SPD]

Hi Guy's

I have a question for the experts here concerning Cobra Jet or 4V nomenclature.
I have a 73 Q code 4V Cleveland. I have heard many stories on whether the 73 4V can be considered a CJ.
As I understand it.
For 71 and 72 the Sales literature used the CJ wording to describe the 4V Cleveland.
This was dropped for 73, however the service manual and Engineering docs still referenced the 73 351C 4V as a CJ.

I have a CJ sticker on my air cleaner and have received some negative feed back on that,
so what is correct?

Thanks
Ray Q.

 

[Sheriff41]

I think it's generally accepted the Q-code is aka CJ. The 71 M-code is usually referred to as 351C-4V and, with its closed chambered cylinder heads (and other differences), it is distinct from the 351C "CJ" engines.

 

[c9zx]

The critics may think the only CJ was the 428 and 429. The CJ decal was dropped sometime in the 1972 model year. Some 1972 chrome lids said CJ and some said 4V. No CJ decals in 1973, no chrome lid, and the air cleaner base was different from 1972. 1971 CJs were very limited and made at the end of the 1971 model year. Chuck

 

[Sheriff41]

As to the negative feedback on your CJ decal, tell them to go pound sand. It's your car and you should configure it the way that you like. I have had Boss 351 decals on my 72 convertible since the late 70s just to generate conversation and to rile people up at car shows.

 

[Topless73Qcode4SPD]

As to the negative feedback on your CJ decal, tell them to go pound sand. It's your car and you should configure it the way that you like. I have had Boss 351 decals on my 72 convertible since the late 70s just to generate conversation and to rile people up at car shows.

Iv'e made a lot of non stock changes to the exterior but would like to keep
the engine bay as accurate as possible. I agree with you regarding it's my car
and I'll make it as unique as I see fit.

 

[markafss]

The critics may think the only CJ was the 428 and 429. The CJ decal was dropped sometime in the 1972 model year. Some 1972 chrome lids said CJ and some said 4V. No CJ decals in 1973, no chrome lid, and the air cleaner base was different from 1972. 1971 CJs were very limited and made at the end of the 1971 model year. Chuck

My 4V came with a chrome cover. I still have it but I don’t have the base. I am the original owner.

 

[c9zx]

Markafss, You have a 1973 4V that came with a chrome lid? If so, do you know the build date of the car? Chuck

 

[Bobby]

I agree with the Sheriff. Its your Mustang and you can call it what you like. If your intent is to go concourse, then you're off beat. If this is your custom vehicle to reflect your desires and personality, then you are right on. I have a lowly H code Mach 1 but I stroked a 351C to 393 with Trickflow aluminum heads etc, etc..... I had custom valve covers made with 393 Cobra Jet lasered on the top of those valve covers. I will also change the decal on the hood scoops to reflect the same. I do not care what other people "think". Its called a resto-mod! Ask those doubters out there if they ever heard of the term!

 

[Rick@NPD]

It's pretty easy to get confused on this topic, and Ford did its part in contributing to the confusion... LOL

I have two Q-code 1973 Fords in my personal collection, both un-restored survivors. A Gran Torino Sport with 38K original miles and a 4-speed, and a Cougar XR7 convertible with 501 original miles.

The Torino has a chrome lid, the Cougar has a blue painted lid. I only remember seeing painted lids on 1973 Mustang/Cougar Q-codes, but that's not to say that chrome lids didn't make it onto some.

There's no argument, the Q-code 351 is indeed a "Cobra Jet" engine. BUT... The correct air cleaner decal for 1973 did NOT say "CJ" on it. It did for 1972, but not 1973. The 1973 Q-code decal calls out "351-4V". But just because the darned decal doesn't say CJ on it does not mean that the engine is not a CJ, because it is. It's just how Ford decided to do it in 1973, period. And it gets damned confusing, because on my factory invoices for both cars, it states "351-CJ". But on the window stickers, it states "351 CID 4V". Why the flip-flopping? I have no idea. Anecdotally, Marti's Ford computer data reads "351-4V CJ".

So it's all over the place, and I don't pretend to know the mystery about chrome lids or painted between various models. But if you're trying to be correct under the hood, the CJ decal should be replaced with a 1973 4V decal. And that replacement, in itself, does not make your Mustang any less of a Cobra Jet than it already is, because it is.

 

[Rick@NPD]

Oh, and also, the original Ford parts texts called the Q-code 351 "CJ" specifically for 1972, but in the 1973 text it's simply referred to as "4V". More confusion, but it really doesn't change the underlying facts.

 

[Topless73Qcode4SPD]

Rick@NPD,

Thanks for taking the time to add to the conversation and taking the pictures.
Your comments support what I have heard in the past...that marketing and engineering were not on the same page for 73.
I think I'll get a sticker that say's 351-4V CJ as per Marti...that will really mess with peoples minds...
Thanks Again..

 

[ROCKET70]

My Grande has a chrome air cleaner and was build early Dec 72. This picture is when I purchased it in 2021 had been sitting since 1979 with 14000 miles all original except oil filter and battery

 

[Topless73Qcode4SPD]

Here's the Marti report for my 73

 

[secluff]

Hi Guy's

I have a question for the experts here concerning Cobra Jet or 4V nomenclature.
I have a 73 Q code 4V Cleveland. I have heard many stories on whether the 73 4V can be considered a CJ.
As I understand it.
For 71 and 72 the Sales literature used the CJ wording to describe the 4V Cleveland.
This was dropped for 73, however the service manual and Engineering docs still referenced the 73 351C 4V as a CJ.

I have a CJ sticker on my air cleaner and have received some negative feed back on that,
so what is correct?

Thanks
Ray Q.

Hello Ray Q,
351 4bl VS 351-CJ debate, one that has seen a lot of air time in the past!
The difference....very little.
It was all a name game with some creative terminology by Ford and the other manufacturers. The engines did receive engineering upgrades to make them compliant with each current model year's emissions requirements. The '72 Q engine content never changed in '72, which is also when the engine's name changed. I owned a 12/71 built '72 Q code Gran Torino Sport with the chrome CJ air cleaner lid and CJ on all the paperwork. My 5/72 built Q code '72 Sport had 351-4V on a chrome air cleaner lid and other paperwork. Same engines, but a well-orchestrated game was going on with the renaming of these engines. The 65-72 Ford Master parts catalog (MPC) identified the 351 Q as a CJ. The 73-79 catalog referred to the 351 Q as a 351 4bl. There were occasional references to the CJ engine in some 73-74 service manuals, but the shop techs knew they were all "Q" engines regardless of what someone called them. The 71-74 engines used the same style block (machined for 2 or 4 bolt mains), crank, cam, springs, etc., with the 73-74 engines receiving cylinder head, intake, and piston changes to accommodate the new EGR systems. The manufactures desire to move away from any reference to performance had a lot to do with the CJ name's disappearance from air cleaner lids, window stickers, and all other printed matter. With gas prices changing almost hourly, economy and safety, not performance, were the new words for the day! The government was always busy finding new ways to spend our money and protecting us from ourselves, and the insurance companies watched the Big Three closely. They wanted to ensure we were offered cars with the same excitement level of a new toaster oven but were slow, safe, and got better fuel mileage than those fuel-guzzling loud performance cars we all loved!

As far as the occasional appearance of the '73 chrome air cleaner lid, that's something I'm working on. It's shown up on too many original owners' early '73 production Mustang, Torino/Gran Torino, and sister Mercury vehicles not to take a second look. Placing a time frame for changes on the assembly line can be challenging. As I've posted before, even when working with before and after dates, as seen in the MPC, that is still like throwing a dart at a revolving dartboard with a blindfold on. These vehicles were not built in consecutive serial numbers. It's possible to have two cars with consecutive numbers but built weeks apart. Running changes is almost impossible to pin down with a line drawn in the sand "This is when this happened" decision.

And, occasionally, you will see my reference to the four-barrel engines as "4BL" instead of "4V". That is a result of dealing with 2, 3, and four-valve 4.6/5.4 engines on a daily basis starting in the mid-90s. They were referred to as 2V, 3V, and 4V engines, so carburated engines were 2BL or 4BL. Just trying to keep one step ahead of the insanity we dealt with daily.

The correct '73 air cleaner decal would specify 351-4V. This is another running change that took place in the early '72 production and continued into the final '74 version of this engine. But, as I have always felt, and others have posted, this is your car. If you are not concourse level showing your Mustang, you should do whatever scratches your itch and feels good. I have always felt the same about the '71-3 ram air cleaner lid. There was NEVER a production-installed decal on the lid, and it always looked like something was missing. The '69-70 Shelby GT-350 decal (351 C.I.D. Ram Air) was the perfect answer for that one and looks great at the same time! Not correct, but it looks right at home! Remember, it's your itch!

 

[Topless73Qcode4SPD]

Thanks Steve
Great write up..

 

[markafss]

Markafss, You have a 1973 4V that came with a chrome lid? If so, do you know the build date of the car? Chuck

I don’t have a Marti, but it was built 11/72.

 

[70cobrascj]

Oh, and also, the original Ford parts texts called the Q-code 351 "CJ" specifically for 1972, but in the 1973 text it's simply referred to as "4V". More confusion, but it really doesn't change the underlying facts.

Rick just want to say thanks for getting the power steering pump paint back in stock.
I picked up two cans.

 

[mrgmhale]

It's pretty easy to get confused on this topic, and Ford did its part in contributing to the confusion... LOL

I have two Q-code 1973 Fords in my personal collection, both un-restored survivors. A Gran Torino Sport with 38K original miles and a 4-speed, and a Cougar XR7 convertible with 501 original miles.

The Torino has a chrome lid, the Cougar has a blue painted lid. I only remember seeing painted lids on 1973 Mustang/Cougar Q-codes, but that's not to say that chrome lids didn't make it onto some.

There's no argument, the Q-code 351 is indeed a "Cobra Jet" engine. BUT... The correct air cleaner decal for 1973 did NOT say "CJ" on it. It did for 1972, but not 1973. The 1973 Q-code decal calls out "351-4V". But just because the darned decal doesn't say CJ on it does not mean that the engine is not a CJ, because it is. It's just how Ford decided to do it in 1973, period. And it gets damned confusing, because on my factory invoices for both cars, it states "351-CJ". But on the window stickers, it states "351 CID 4V". Why the flip-flopping? I have no idea. Anecdotally, Marti's Ford computer data reads "351-4V CJ".

So it's all over the place, and I don't pretend to know the mystery about chrome lids or painted between various models. But if you're trying to be correct under the hood, the CJ decal should be replaced with a 1973 4V decal. And that replacement, in itself, does not make your Mustang any less of a Cobra Jet than it already is, because it is.

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Those are some nice cars! 501 miles on the Cougar, simply breathtaking. I though we had done well to have acquired a 1973 Mustang Convertible with under 20,000 original miles. It was literally barn stored for over 40 years when its owner became very ill and later passed away. It is (also) in excellent preserved condition, where the prior owner replaced the fabric top, the tires (sidewalls on originals tires were cracked), and replaced the dog dish wheel/hubcaps with Magnum 500 wheels. I have done some tasteful upgrades. But, for the most part it is a fairly base convertible that has been spruced up with aftermarket Classic Air air conditioning, and some electrical enhancements to help make it even more pleasurable to drive.

Thank you for sharing the photos (and for your insights on the initial subject matter in this thread).

 

[Stanglover]

I didn't come to Canada and Canadian Fram until March of 73 where I worked as a model maker, as we were called at that time, in the air cleaner department. Prototype specialist would have been a more fitting name.
At that time, much was changing and most of the pre 73 work was well behind us, so I don't have a lot of knowledge of that era. However at Fram, we did make the snorkels (inlet tubes) used on the 71-73 17" Ford air cleaners. Ford stamped the lower shells and lids at their own plant using Fram tooling. This of course, for me, is passed on information. I do remember seeing cases of chrome 17" lids which I believe were also used on other air cleaners, probably Chrysler. The shells were basically the same but with model specific changes.
I still know a few old timers from the plant who might remember more about the Ford production.
My thinking on the use of chrome lids on some 73's is simply using up stock. After all, chrome was "top shelf" and more expensive.
I'll possibly be seeing a couple of the old farts on Thursday at our cruise night (if it doesn't rain!!) and I'll see if I can get more insight. As said, I came in at the end of this era, plus it was 50 years ago!!

EDIT: I did talk to a couple of guys last night, but wasn't able to shed much light on it. They do remember the chrome 17" covers and I was correct on the Ford inlet tubes being made at Fram and shipped to Ford for paint and assembly.
Unfortunately many of the people who would have had better knowledge have passed away.
Sorry, that's all I've got.

 

[mrgmhale]

You received a lot os really good information from several folks who have a much better understanding of what Ford was doing with its nomenclature re: their higher performance engines. Despite the 351 being regarded as a 4v or a CJ, what I have come across for 1973 is the engines (to include the 351) were detuned with their valve timing, by I think 4 degrees, in order to meet the emission standards being jammed down our throats back then. Regardless, even if the engines were detuned it does not detract from what great cars they were and are.

In the event you feel compelled to change any stickers you may or may not have, I have found ECS Automotive concepts offers a really nice selection of tags and stickers. I have purchased side glass from them for one of our 1973 Mustangs, and for our 1969 Shelby GT500. In both cases they were able to etch the glass with the correct CarLite logo, the type of glass, and the correct date code from the original glass. I am very pleased with what they sent to me. Here is their web address for anyone interested:

https://ecsauto.com/

A quick aside, The emission control engine vacuum schematics (aka "calibrations") are generally available in the Forel Publication 1973 Shop Manual, in Volume 6 (web site below). But, interestingly the calibrations for the 351 4v engine are missing. I came across them from "somewhere" and after removing the copy protection scheme from the Shop Manual PDF file I inserted the two missing calibrations. I have attached those missing calibrations to this post for anyone who may need that information.

Also, prior to 1973 the various manuals I have seen do not include engine vacuum schematics/calibrations. They include the vacuum system for HVAC, and some other vacuum related devices, but that is about it. Well Mustang Barn was nice enough to put together their own calibration specs for 1967 - 1972 Mustangs (which I presume covers Ford/Lincoln/Mercury also). With their knowledge and approval I