Difference in 32V heads

[jay87lx]

I a need of a passengers side head for our '03MM. I posted in our classified here and just started to look around and am seeing some differences. For instance, I just found a set for $850 on "03-'04 Cobra parts for sale" on FB- He says they are "4 thread castings"
What does that mean and what should I be looking for to source a head from? Are the 32V lincoln navigators the same engine and heads?

[fastblackmerc]

I a need of a passengers side head for our '03MM. I posted in our classified here and just started to look around and am seeing some differences. For instance, I just found a set for $850 on "03-'04 Cobra parts for sale" on FB- He says they are "4 thread castings"
What does that mean and what should I be looking for to source a head from? Are the 32V lincoln navigators the same engine and heads?

The "4 thread castings" means there are 4 threads in the spark plug holes. More desirable than the 3 thread ones.

Someone will chime in with what heads fit.

[ctrlraven]

3 Thread? To my knowledge there was only 4 thread (early builds) and 9 thread (most 04's and later).

Any passenger side head from a 03/04 Marauder, 03/04 Mach 1 & Cobra and 03-05 Lincoln Aviator will be the same.

[fastblackmerc]

3 Thread? To my knowledge there was only 4 thread (early builds) and 9 thread (most 04's and later).

Any passenger side head from a 03/04 Marauder, 03/04 Mach 1 & Cobra and 03-05 Lincoln Aviator will be the same.

That was just a WAG.........

[Logizyme]

Regarding 4V heads there are 3 Major revisions:

The "B" heads which have individual intake ports per valve used on all 4.6 4v applications from 1993-1998, Mark 8s, Continentals, and 96-98 Cobras.

The "C" heads which have one intake port feeding both valves used on most 4.6L and 5.4L 4v applications including Cobras, Mach1s, Marauders, aviators, and navigators.

The "GT" heads which have several unique variations, including valve spring design, head port shaping and design, intake and exhaust port and bolt location, making their compatibility with non-GT designed parts difficult, applications are limited, and include the Ford GT, 05+ GT500, and the 5.0L(4.6L based) Cammer race engines.


Moving forward to your question, there was a design variation around 2005 for the "C" heads which is most easily identified by the number of spark plug threads, 99-04 heads are "4 thread" and 05+ are "9 thread". While there are plenty of suggestions to other improvements within the revised head, such as coolant passages improved to reduce the need for a cooling mod, but there is limited-to-no proof of any such changes. These are still the more desirable heads compared to 4-thread.

Any "C" head will be correct for the Marauder application, while a 9-thread head would be more desirable, functionally they should be considered practically identical.

In the case of your specific question, yes the head described would be correct.

[moffettlancaste]

I'm asking on this tread, because I don't know anything.My apologies to jay. My question is can the 4 tread heads be taped to get the 9 treads. My apologies to everyone.

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[chief455]

I'm asking on this tread, because I don't know anything.My apologies to jay. My question is can the 4 tread heads be taped to get the 9 treads. My apologies to everyone.

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no, the holes can not be tapped
but
yes, inserts can be put into the 4 thread heads that make the spark plug holes stronger and utilize 9 or more threads for seating.

[Ourobos]

Marauder, Aviator, Mach 1, 03/04 Cobra.. Even the cams were the same specs.

[chief455]

here is some timeline casting and revision info on these heads:
http://www.terminator-cobra.com/castings.htm

[moffettlancaste]

no, the holes can not be tapped
but
yes, inserts can be put into the 4 thread heads that make the spark plug holes stronger and utilize 9 or more threads for seating.
Thanks, were the problems related to horse power or boost? Should the inserts be installed at tune up as a matter of course? I have a 03 MM that needs some work to get it ready for upgrading. Thanks for your help, which I will need a lot of

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[RubberCtyRauder]

Problem was poor casting design only allowed 4 threads.

[chief455]

Problem was poor casting design only allowed 4 threads.
result is spark plugs can blow out of the holes, even stock engines.
the aftermarket inserts are the way to go.

[moffettlancaste]

result is spark plugs can blow out of the holes, even stock engines.
the aftermarket inserts are the way to go.
Thanks again, I will put that on the top of my to do list. Are the inserts easy to find?

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[RubberCtyRauder]

They are called Timeserts