Author Topic: pre May '71  (Read 219 times)

Offline desperadoron

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pre May '71
« on: January 28, 2018, 09:06:25 PM »
did any of the early '71 mustangs have the 300 hp 351 c motor?

Offline nham3407

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Re: pre May '71
« Reply #1 on: January 29, 2018, 10:55:59 AM »
Not per the AMA Specs.  Not to say something may have slipped into the production run outside of the planned equipment, but I am not aware of any.  I have included the first page of the AMA specs detailing the engine combos. The second page was 429 combinations so I did not include as it was beyond your question.

67 GT S-Code, San Jose, 06/67
72 Mach 1, Dearborn, 01/72
68 Merc. Cyclone, Lorain, 06/68

Offline desperadoron

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Re: pre May '71
« Reply #2 on: January 29, 2018, 11:05:55 PM »
  I though I read a article that said some ordered before May of '71  had the 300 hp. I ordered mine early April . what other ways can you tell it has the bigger exhaust  ports?

Offline J_Speegle

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Re: pre May '71
« Reply #3 on: January 29, 2018, 11:42:36 PM »
Be careful of believing everything you read.

Haven't studied the issue but I would look to casting/engineering numbers on the heads and or the exhaust manifolds. Don't know if the heads your referring to are open or closed chamber heads but those have different markings in the upper corners visible with the valve covers on.

Considering that emissions standards can chance during the production year would have thought (may not relate to this subject at all) the change would take place at the end of the calendar year.
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline cobrajet_carl

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Re: pre May '71
« Reply #4 on: January 30, 2018, 10:52:26 AM »
did any of the early '71 mustangs have the 300 hp 351 c motor?
Well at least one early 71 had the closed chamber 4V heads; I had one built in September of 70. I think the heads were D1AE with the 4. But technically I guess it was the 10.7CR 285HP instead of the 11.0CR 300HP. So if you were wondering if any 71s had the D0AE heads, almost certainly not. The D1 heads have a slightly larger combustion chamber than the D0 heads which results in lower CR and HP.

There is an August 70 on ebay that has the D1AE heads.
The open chamber 351CJ was available starting in May but only 144 were made. It was a "Q" engine code instead of an "M."

Interesting that the AMA spec docs don't mention the Boss engines for either 70 or 71.
« Last Edit: February 01, 2018, 10:48:36 AM by cobrajet_carl »

0F05R1173xx C6 A/C Grabber Orange/Black
0F05R1254xx C6 A/C Bright Gold Metallic/Ginger
0F05R1058xx 4sp Yellow/White
0F05Q1394xx 4sp Medium Lime Metallic/Ivy
0F05H1338xx 3sp Red/White
1F05C1238xx 4sp Goldenrod/Ginger
1F05J1345xx 4sp Red/Red