'72 HO vs 72' CJ engine...

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Kit Sullivan

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The '72 HO "R"- code engine has long been heralded as an "almost-BOSS 351" and talked about in revered language, while the '72 CJ "Q"-code engine has enjoyed less respect.

The HO was rated at 275 hp, while the CJ is rated at 266. Not a huge difference, to be sure.

The HO-equipped '72 Mustang was at best a low-to-mid 15 second car....nothing really spectacular when considering it had a 3.91 rear gear.

I have driven a few BOSS 351s over the years, as well as a couple '72 HOs. There really is no comparison...the HO is NOT in the same league as the BOSS 351.

Acceleration in the BOSS is ferocious...not so much in the HO.

Considering that the 3.50 gear is the stoutest available in a CJ, it is understandable that the 3.91-equipped HO would be the quicker of the two.

But I think it is the 3.91 vs the 3.50 that makes the difference, not so much the HO vs the CJ. Put a 3.91 in a CJ with a 4-speed, I am sure It will run near-identically to an HO Mustang.

And I am talking about stock engines with all emissions and timing adjustments as from the factory. A few very sime tweaks ( especially to cam timing and the ignition system) and a CJ or an HO can easily keep pace with a stock BOSS 351.

 
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c9zx

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The compression ratios and retarded cam timing really hurt the HO and CJ code cars. The 4300D carb did nothing to help any of the cars it was used on.

My bone stock 72HO did run better than my bone stock 71 351 4V car. The 71 B1 car was not stock so hard for me to compare it to the others. Chuck

 
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Kit Sullivan

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Do you feel the 3.91 was the reason it ran better? Or do you feel the HO was just a better overall engine than your '71 "M"-code?

 

c9zx

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Do you feel the 3.91 was the reason it ran better? Or do you feel the HO was just a better overall engine than your '71 "M"-code?
The M code had a 3.50:1 gear. The HO the 3.91 which did help it but, the solid cam and more aggressive cam timing events allowed it to rev significantly higher to take advantage of the 4V heads. Just my opinion. Chuck

 

72 R Code

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I had mine on the drag strip and several timed in 73 and 74. Completely stock with street tires and no modifications it would run 14 flat. After changing the rear end to 4.57 and getting better tires and open exhaust I got it down to high 12s.

 
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Kit Sullivan

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Really, 14.0s totally stock? That is very impressive!

I have driven a few stock '72 HOs and none of them could do that.

Just so I can be sure we are comparing apples/ apples: you are talking about a stock '72 HO, right? Stock timing, exhaust, carburetion, tires, suspension, etc...?

No traction bars, open air cleaner, disconnected smog stuff?

That is a great time for that car. I will hazard a guess that your driving skills were a big factor in that also. Your 60-footers must have been very good.

 

72 R Code

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When it would hook up it would really run. The traction bars and other mods came later. Probably the biggest gains came from the 4.57 gearing and M&H Racemaster drag tires. I always used the stock carb. I was a lot younger then and the best times came at the Muncie Dragway. We always ran at night there. It was usually a little slower at Indy.

 

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I hope someone can help me ...my VIN number is very unusal and not the typical vin number format and I'm confused and cant properly decode it but im hoping im right cuz maybe just maybe its a rare car, (doubt it) could be a R code 351 HO? vin hinting a 1972 but it has 1973 fat lip bumper and rear has 73 bumper and it has a 73 grille and the 351c has a 2 barrel on it? R code would have a 4 barrel, its a crazy car so here is my unusual vin number...help me decode...GOOD LUCK

vin# F2R11X146864

 
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73pony

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That does not look like any Mustang VIN I have ever seen. Can you double check or take a pic? Format looks similar to mid 60's chevy trucks.

 

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That does not look like any Mustang VIN I have ever seen. Can you double check or take a pic? Format looks similar to mid 60's chevy trucks.
My VIN doesnt match any sort of Ford VIN format at least for Mustangs, this is based from my Title and the tag plate in the windshield/dash, they both match and its very unusual formatted code, is it a Overseas VIN? who knows, Ford known to do crazy things. I just hope it ends up being a rare unusual car, that would be nice for a change! If its an "R" code its really valuable but it certainly doenst have a "R" code engine in it now and it has a C6 tranny and I think all "R" code for the era were 4-speeds only? But if I have De-tuned boss 351 from 1972 that would be awesome!

I need someone to steer me in the right direction to do more research , I come up empty with google, maybe Mardi Report? My car is under wraps so I have to spend time and uncover it and then I will take photos of all the tags and nameplates on dash and the door

 
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Ford would do some very strange things to corporate test cars to be able to put them out without fed approval. They were test cars and not ever meant to be titled. In the 1980's I turned down the only King Cobra Torino made the only number it had was EXP-429. It was sent to Bug Moore to test for NASCAR use.

There are three of the never made 427 Mustangs in this area they also have strange VIN# but are real.

You might have a test base car that made it out. Hope Steve sees the post he is up on all the Ford numbers.

I would give Marti a try for $18.00 it will tell you something and he can do quick if you contact personally.

 
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Those ET's do not sound unreal heck I had a flathead that would turn in the 15's have timing slips stashed somewhere ran T or U stock AHRA. A good 289 would do in 13's for a HiPo in F stock back then.

 

supercoupe

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Ford would do some very strange things to corporate test cars to be able to put them out without fed approval. They were test cars and not ever meant to be titled. In the 1980's I turned down the only King Cobra Torino made the only number it had was EXP-429. It was sent to Bug Moore to test for NASCAR use.

There are three of the never made 427 Mustangs in this area they also have strange VIN# but are real.

You might have a test base car that made it out. Hope Steve sees the post he is up on all the Ford numbers.

I would give Marti a try for $18.00 it will tell you something and he can do quick if you contact personally.
if its only $18 then worth a try, since the odds are against me to find info on this I dont want to add to the equation buy throwing money at someone of which it leads to a dead end, I sent an email to Mustang monthly on this but haven't heard from them, they wrote an article about weird VINS way back in 2002, I think Jim Smart is the go to guy on this? (mustang Monthly tech editor)

I guess what Im asking is this make it worth more than the usual VIN model?

 

supercoupe

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Ford would do some very strange things to corporate test cars to be able to put them out without fed approval. They were test cars and not ever meant to be titled. In the 1980's I turned down the only King Cobra Torino made the only number it had was EXP-429. It was sent to Bug Moore to test for NASCAR use.

There are three of the never made 427 Mustangs in this area they also have strange VIN# but are real.

You might have a test base car that made it out. Hope Steve sees the post he is up on all the Ford numbers.

I would give Marti a try for $18.00 it will tell you something and he can do quick if you contact personally.
if its only $18 then worth a try, since the odds are against me to find info on this I dont want to add to the equation buy throwing money at someone of which it leads to a dead end, I sent an email to Mustang monthly on this but haven't heard from them, they wrote an article about weird VINS way back in 2002, I think Jim Smart is the go to guy on this? (mustang Monthly tech editor)

I guess what Im asking is this make it worth more than the usual VIN model?
Mr. Mardi came up with nothing, I sent an email to Mustang Monthly no response yet, how is this so tough? one rumor was it was made in mexico? maybe it was stolen and retagged and the DMV didnt notice?

 

OMS

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Ford would do some very strange things to corporate test cars to be able to put them out without fed approval. They were test cars and not ever meant to be titled. In the 1980's I turned down the only King Cobra Torino made the only number it had was EXP-429. It was sent to Bug Moore to test for NASCAR use.

There are three of the never made 427 Mustangs in this area they also have strange VIN# but are real.

You might have a test base car that made it out. Hope Steve sees the post he is up on all the Ford numbers.

I would give Marti a try for $18.00 it will tell you something and he can do quick if you contact personally.
if its only $18 then worth a try, since the odds are against me to find info on this I dont want to add to the equation buy throwing money at someone of which it leads to a dead end, I sent an email to Mustang monthly on this but haven't heard from them, they wrote an article about weird VINS way back in 2002, I think Jim Smart is the go to guy on this? (mustang Monthly tech editor)

I guess what Im asking is this make it worth more than the usual VIN model?
Mr. Mardi came up with nothing, I sent an email to Mustang Monthly no response yet, how is this so tough? one rumor was it was made in mexico? maybe it was stolen and retagged and the DMV didnt notice?
What numbers are on the shock tower

Door tag ?

The only odd VIN's I have seen like that were state issued re-vins

 
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