CJ or not CJ

Hey Guys

done plenty of research on my 73 Q code but sometimes it just becomes more confusing not sure if its the scotch or what but my question is

1 were there cobra jets in 73

2 what qualifies a 351 as a CJ

3 how do we identify a CJ apart from pulling the sump off to see the 4 bolt mains , is this right?

4 mine is a 73 Q code i have the marti report it says Q 351 4V Engine

should it say CJ if it is a CJ ?

and just to make it more confusing im the 3rd owner a doctor bought it in 73

1 has no power steering as not stated on report

2 has air cond

3 had dealer fitted ram air as i know factory ram air wasnt available for Q code

4 diff is 9 conventional 3.25 non posi track

hurst shifter with dealer T bar Knob

it just seems a weird combo no power steering but all the go fast bits but no posi trak?

so if any of this makes sence im just wondering if she,s a cobra jet or not

thanks guys

Dave Tommy

Well..It is a cobrajet motor pretty much...Ford just dropped the Cobra jet name for 351 4v...It still had the same spread bore carb as a cobrajet.

..They retarded the cam i guess a bit.....And some 1973 4v heads got smaller valves than other's...Mine got 2.19 sized valves in it..some i guess got smaller ones.

And are you sure it had dealer installed ram air? All 73 hoods are predrilled for ram air...I use to think mine had ram air installed at one time...But come to find out..All hoods are predrilled..Or does your still have some of the ram air equipment left on it?

You can pull the oil pan off and check for 4 bolt mains ..Or if you can find the block numbers..If you can see them..They are hard to see thou..hidden on the side of the block "cant remmeber which side" but under the exhaust pretty much.

As for powersteering...Not sure...I use to think it was standerd...Im sure Don from oms knows the anser to that one..cause my marti report states power steering...Air con and stuff..Im suprized it does not have power steering.

And that is a odd combo..But i guess it what some one wanted...I got the posi track 325 on mine.....You got the marti report on it?

I always thought a CJ meant it had 4 bolt mains.

I always thought a CJ meant it had 4 bolt mains.

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Well little more than just that...But not much...CJ's got the spread bore carb like the boss carb..autolite or motorcraft 4300d....Regular 4v 351 clevelands got a square bore carb and i think 2 bolt mains.

I always thought a CJ meant it had 4 bolt mains.

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Well little more than just that...But not much...CJ's got the spread bore carb like the boss carb..autolite or motorcraft 4300d....Regular 4v 351 clevelands got a square bore carb and i think 2 bolt mains.

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Not positive but, I don't think there was a 351 4V CJ and a reg 351 4V

I think in the ford lineup for 72 it was a 351 2V or 351 4V and the 4V's were called cobra jets.

Same in 73 less the cobra jet name and diverter door air cleaner

I always thought a CJ meant it had 4 bolt mains.

Click to expand...

Well little more than just that...But not much...CJ's got the spread bore carb like the boss carb..autolite or motorcraft 4300d....Regular 4v 351 clevelands got a square bore carb and i think 2 bolt mains.

Click to expand...

Not positive but, I don't think there was a 351 4V CJ and a reg 351 4V

I think in the ford lineup for 72 it was a 351 2V or 351 4V and the 4V's were called cobra jets.

Same in 73 less the cobra jet name and diverter door air cleaner

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You are right...Plus was not talking about 1972-3 there....It was a 351 Cobra jet.. Then they put a stop to the 2 bolt main 4v 351 in 71....What confuses alot of people..When they dropped the CJ name from the Cobra jet motor in 1973..Yet alot of motor guys still call it a CJ..hehe ..So when looking up the info online..They will call it a 351 4v CJ alot..lol

I know it's not "correct" for 73, but low compression, 4 bolt mains, and 4V heads = CJ to me.

I know it's not "correct" for 73, but low compression, 4 bolt mains, and 4V heads = CJ to me.

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Sounds right to me...by the way, the 73 shop manual calls it a CJ all over the place.

Jeff

Regarding 4 bolt mains.

4 Bolt mains were primarily BOSS motors. It has been determined a few 4 bolts slipped through the line into standard 351C 4V's. But those blocks would be D1AE or D0AE.

CJ in regards to the 351C is strictly a marketing term. It is IMPOSSIBLE to determine a CJ block from a non CJ block. CJ Heads would be 4V. But, not necessarily closed chamber. Not necessarily open chamber due to the years involved.

On the other hand, if you have a 428 CJ...well, that would be a different story.

I disagree. Ford used 351 CJ to differentiate the "other" 4V 351C from the 351 HO in 1972.

Thanks Guys now im even more confused lol

no not really thats all good info hyena it has functional ram air on it now

and i have marti report which doesnt mention pwr steer

i just found a really cool book/magazine in the glove box called 73 Ford Mustang illustrated facts book compiled by editors of mustang monthly magazine it has everything about all the models released in 73 from convertibles to mach 1s this thing looks like it was printed in 73 wow its got everything they were optioned with

time to read

then i ll be the expert hahah

Dave tommy

Tommy,

I also own a 73 Q code and it does seem to be a bit confusing. Check out these web links:

http://www.mustangspecs.com/years/73.shtml

http://www.mustangspecs.com/years/72.shtml

http://www.mustangspecs.com/years/71.shtml

Looks like for 72 and 73 a Q code is considered CJ. For 71 things were different... Just me 2 cents.

Good stuff guys...I have a 73 Q code also.

Just to clear some stuff up...the Cleveland block used for 72 and 73 mustangs was a D2AE-CA. This same block part number which is stamped on to the housing is used for BOTH the 2V and 4V cars. The ONLY way to tell if it is a CJ block is to determine if it had 4 bolt mains.

The only heads used on the 73 CJ were open chamber heads, the carb was a 4300D spreadbore and had a special intake manifold to fit the carb along with different exhaust manifolds. The CJ's also got a different distributor with special advancing.

The 73's did not distinguish between a 4V car and a CJ car...they were one and the same. If you look through the shop manual the term CJ is used all over for 73's.

Jeff

I always thought the biggest performance difference was result of the factory installed mechanical lifters and cams used on the scj's and the 71 Boss, which we can all improve on now. The nodular blocks in the Boss's is another story of course !

thanks again guys

I just was watching this show on youtube and he had a 72 mach 1 motor next to a 73 mach 1 the difference was the exhaust manifold outlet holes were much bigger on the 72 than the 73 and it was clearly bigger with all the pollution emissions and govt control in 73 i think the difference between the claimed 277 hp of the 72 and 266 hp of the 73 it was an easy fix for ford to restrict the exhaust outlet im hoping for some good gains when the hooker long tube headers go on next month

thanks again

Dave Tommy

thanks again guys

I just was watching this show on youtube and he had a 72 mach 1 motor next to a 73 mach 1 the difference was the exhaust manifold outlet holes were much bigger on the 72 than the 73 and it was clearly bigger with all the pollution emissions and govt control in 73 i think the difference between the claimed 277 hp of the 72 and 266 hp of the 73 it was an easy fix for ford to restrict the exhaust outlet im hoping for some good gains when the hooker long tube headers go on next month

thanks again

Dave Tommy

Click to expand...

Well it's U tube

All the 71-3 4 V's used the same exhaust manifold

Only Boss 351's had one that was opened an extra bit - not much though

ok it was the guy s from that mustang medic show the 2 motors had distinct size differences but who knows

it was only poo tube so im sure you are right

thanks

Dave tommy

72 351 engine line up:

351- 2v

351-4v

351-4v "HO"

When the HO was dropped early in production run, the "regular" 351 4v was renamed "Cobra Jet".

73 351 line up:

351-2v

351-4v "Cobra Jet"

All 73 engines received EGR systems and retarded timing chain sets. Most 73 4-v Cleveland heads received smaller 2-v sized intake valves.

The 73 "CJ" engines were severely underpowered as compared to previous 351 4v Cleveland's.

Wow...there is a lot of bad information in this thread. After my rant below are answers to your original questions...

As I recall, you wanted to be able to tell if a block was a CJ or not.

First, there is NO WAY to confirm the block is a CJ. You can discuss date codes on the block, and certainly 72 casting were put in 73 Mustangs....how else would a 73 Mustang bought in October of 73 have a engine. However, it is not outside of the realm of possibilities a 71 casting made it into a 73. And certainly, 73 castings were found in Mustangs. I had one. From the dealer. June 1973.

Second, regarding 4 bolt mains. I have torn apart 3 351C motors- 1971,1972, 1973. All were factory 4V motors. Zero had 4 bolt mains. As stated previously, I am unaware of any 4 bolt 351C motor except the Boss and a few stragglers in 1971. It is fairly easy and not uncommon to have builders add the bolts. But a 4 bolt main is no guarantee of a 351C CJ.

Third, in the 1973 Ford Service Manual and Specifications Manual(Both attached), you will find the following:

1. The SPECIFICATION MANUAL(Second and final printing) does not mention the HO. Only the CJ.

2. The Service Manual mentions the CJ once. In regards to the VIN. This is where the famous Q CODE designation is found. If someone can show me other pages mentioning CJ, I would sure like to see them.

3. The service manual mentions HO multiple times. In fact, it is pretty interesting to review the differences(very few and very slight) between the HO and non HO motor. It is interesting the piston clearance is greater in the HO.

Now, are the manual and specification booklets perfect sources of information. NO. Try to find a reference to the 351 BOSS in the 1971 Ford Service Manuals.

In the end the use of the term CJ was just a marketing ploy. tHO was probably used, but then someone realized it was "false advertising", so they went to the tried and true CJ from the 428 and 429 glory days.

VariousEngine.pdf

VariousEngine_SpecBook.pdf

1. were there cobra jets in 73. Well, not technically a cobra jet. A CJ.

2 what qualifies a 351 as a CJ See Attachments

3 how do we identify a CJ apart from pulling the sump off to see the 4 bolt mains , is this right? WRONG

4 mine is a 73 Q code i have the marti report it says Q 351 4V Engine

should it say CJ if it is a CJ ? CJ MIGHT BE ON THE AIR CLEANER DECAL and on the EMISSION STICKER ON THE VALVE COVER.

and just to make it more confusing im the 3rd owner a doctor bought it in 73

1 has no power steering as not stated on report. Doesn't matter

2 has air cond Doesn't matter.

3 had dealer fitted ram air as i know factory ram air wasnt available for Q code

No Big Deal.

4 diff is 9 conventional 3.25 non posi track...not an issue

hurst shifter with dealer T bar Knob. Not an issue.

it just seems a weird combo no power steering but all the go fast bits but no posi trak?

Doesn't matter.

so if any of this makes sence im just wondering if she,s a cobra jet or not

thanks guys

Dave Tommy

If your VIN is a Q code as shown on page 1 of the first attachment, and the motor is original to the car(Don't know how you determine that), then it would be a CJ. I don't think the term COBRA JET was used. CJ was used to imply Cobra Jet...thereby the lack of cobra's anywhere on the car.