V6 head interchangeablility

b\o · **V6 head interchangeablility**

All of the following questions are about the 3.8 engine.
1) Will heads from the early ('84-'87) fit later '03 block?
2) What are the differences between the '84-'87 heads and the following years through '03? Did the exhaust port pattern remain the same?
3) Is '98 an odd ball year because of the counter rotating balance shaft? or?
4) How did the compression ratio's change from '84 through '03?
5) Is the imbalance on the V6 50oz?
6) What type of rockers did the '84-'87 heads have? Will those from an '03 head work with a '84 head? Push rods?
7) The book I have on Fords claims that the heads on V6 Mustangs were cast iron. I have not found any other reference to a cast iron head for any ford V6. Were any ever made?
8) Will the front cover from a '84-'87 fit on a '03 block so that a distributor can be fitted? Or other options/suggestions for distributor ignition?

97Stallion · 03-10-2005, 12:57 AM

I need to ask why you're going to use 84-87 heads first. Those heads are by far the worst you can think of in terms of flow. Also, I do not believe that the pre 88 3.8 blocks and the same as the 88-04 blocks. I'm sure they are quite similar but i would think most of the stuff is not interchangible.

RGR · 06:41 AM


Quote: Originally Posted by b\o All of the following questions are about the 3.8 engine. 1) Will heads from the early ('84-'87) fit later '03 block? 2) What are the differences between the '84-'87 heads and the following years through '03? Did the exhaust port pattern remain the same? 3) Is '98 an odd ball year because of the counter rotating balance shaft? or? 4) How did the compression ratio's change from '84 through '03? 5) Is the imbalance on the V6 50oz? 6) What type of rockers did the '84-'87 heads have? Will those from an '03 head work with a '84 head? Push rods? 7) The book I have on Fords claims that the heads on V6 Mustangs were cast iron. I have not found any other reference to a cast iron head for any ford V6. Were any ever made? 8) Will the front cover from a '84-'87 fit on a '03 block so that a distributor can be fitted? Or other options/suggestions for distributor ignition?

My best educated guesses: *noted with *** for guesses, otherwise
it is info I have checked...

1. *** Yes, as far as I have seen, and I did a set for RPM before I started
teaching him porting, that used later heads on an early block. So early heads
will fit a later block, they just might have issues with accessories and such.

2. Exhaust port pattern was same as far as header/manifold and same as
*** far as port shape as much as I could tell. Best factory header was by
far the 94-98 Mustang units, get those for any swaps.

3. They had header changes, slight but they were different. *** I think it
was an air injection tubing change, but guys use the headers from the earlier
years on the odd-ball 98's with minor tweaks.

4. They generally went UP. For the old carbed and CFI stuff, I have no figures
but It was close to or at 9:1 and the current stuff (03 at least) is 9.36:1 ...

5. *** I believe it is, I've always heard that it's the same as the later 5.0's
and it is externally balanced until a split year at (late '00 or late '01) can't
remember which year they did the mid year change. The later ones, including
you '03 are internally balanced, same as neutral balance. That part I know for
a fact.

6. *** Rockers are interchangeable (AFAIK) and PR's should be the same.
Just measure the pushrods. If you do go thru with this, keep your '03 PR's
just in case. I believe there might have been a change between roller and
flat tappet years in pushrod length. The roller tappets (lifters) are taller in
most engines that went roller, using a shorter pushrod.

7. No, the earliest carbed and CFI heads I have seen on a 90* 3.8 V6 were
all aluminum. Your book is probably referring to the 60* V6 which is the 2.8,
2.9. 3.0, 4.0 family. Things like Taurus, Ranger, etc. Entirely different engine.

8. *** It probably will, but definitely a step backwards. (that part is a FACT!)

Sounds like you have an '03 and wanting to use it in an older V6 application.
It would be almost as easy (IMO) to get a computer in there and keep all
the extra HP the '03 has from the EFI and SPI heads. The only advantage
you would get is the new block and roller cam, and that roller is mighty weak.
You should rebuild your 83 or whatever year it is. Much easier. I even have
a performance cam for the early V6, it's bigger than the '03 roller by far,
even if you block is toast (busted cylinders or some such thing) you can get
a cheap block from the JY and rebuild that easier than swapping in a new
block that takes all these changes. The only benefit you will get is the roller
cam block and the fact that it is new. Tell us what you are doing and we can
at least give you more specific info, if you decide to go about it this way.

What year exactly are your heads and stuff? Carbed and single port (EFI)
stuff has been mixed successfully, but those look the same except for the
EFI bungholes in the heads for the later years (88-98) Ports are bigger
in the EFI heads too.

That's all I got for now, if we can get Mikael in here, he is the one that put
my ported EFI heads on an '83 and that is kinda the reverse of what you
are doing, it will help to know partly what he did. Make sense?

Danger Dude · 03-10-2005, 06:49 AM

As to the question about 98's being odd balls. RGR is right. The 98 changes were in part emission requirements that changed for that year. They also have a short block that is like a 99+ as opposed to the 94-97 having the same block

RGR · 03-10-2005, 06:52 AM

Thanx for the clarification DD!

ole Skillet head

b\o · 03-10-2005, 07:27 AM

WOW! Thanks for input. I knew someone would have tried this before. I have a Model A that I am working on and the V6 engine looks good because of its shorter length than the 302 (4 inches). I am going to use a C4 from a Mustang II with the 141 tooth flexplate to reduce tunnel requirements. I have not been able to find a stand alone computer for the split port EFI set up? They are out there for non-split port, maybe I didn't look far enough???? The original computer (which I don't have) is too complex and requires a lot of things (EGR/oxy sensor/etc) and is beyond my ability. I have the '03 engine and am investigating the possibility of putting on a 4 barrel carb with an intake from Morana Eng. in Canada. My original understanding was that the intake would replace both upper and lower intake, reality is that it only replaces the upper and you have to wire the split port control open, (Mickey Mouse) and I don't want to go that route. Morana suggested the 84-87 heads. He has been a very good/experienced source in the past but before I leap with more $$$$$$ I wanted more input re this post. The books I have say that the 03 engine is a copy of the Supercharged earlier version and stronger? It looks like I need a new book. Understand that I am not looking for low numbers at the strip but reliability and uniqueness. I have been trying to figure out a way to use this engine because of its advantages and low milage but waver between it and a 302 that would have a world of available accessories. Any input appreciated. b\o

RGR · 03-10-2005, 07:40 AM

Ahhh, that makes it much more clear!

A stand alone computer for an earlier V6 could be made to work,
but you would need to do the fuel rail conversion and add a return
line and regulator. Maybe more is needed...
I want to work out a DIY kit for the fuel rails because the demand
is there for it, for 94-98 guys swapping up to 99^ engines. The 99^
has a "returnless" fuel system, while the older ones have a return.

The 99-04 V6 is a hot little engine, weighs less than an old 2.3 OHC 4 banger,
makes V8-like power stock, and even more modified. Keeping the EFI on there
and adding a cam and tune really wakes it up! Some guys have got close to
220 RWHP with a 5 speed using my old cam and no porting. The new cams
promise even more, but that is another discussion, at this time just keeping
the EFI would be a big help. C4's have been used behind these later engines
and quite successfully. I'm pretty sure 50 oz. is the balance weight. The
flexplate from the '03 may fit the C4... it would be nice!

A vintage Ford with this "hi-tech"/old tech (pushrod) V6 would be

SWOOT!!!

(my son's word, sweet + woot = SWOOT

)

RGR · 03-20-2005, 06:50 PM

Update b/o???

Ponycarman · 03-20-2005, 08:29 PM

Here is something to consider, and mind you I am not a fount of Ford knowlege and I am uncertain exactly how the split port is designed to work.

If my assumption that the split port runner change merely happens at a set RPM and isn't gradually applied is correct then you can easily use existing hardware to control it. A RPM activate shift light setup could be used to flip the ports instead of turning on a shift light. As for the computer, look up Megasquirt, http://www.megasquirt.info/ The latest iteration can do everything you want and none of what you don't want in controlling fuel AND ignition.

If the DIY assembly of the computer is more than you want to tackle there are people who assemble, test and sell them. You can usually find them on EBAY.

You will have to wire it up though and tune it.

Steve

RGR · 03-21-2005, 07:09 AM

I believe the IMRC's open gradually. That may happen due to the
IMRC motor design though, it may open gradually with a set computer trigger point.

slvr2000stang · 03-21-2005, 10:17 AM

5. *** I believe it is, I've always heard that it's the same as the later 5.0's
and it is externally balanced until a split year at (late '00 or late '01) can't
remember which year they did the mid year change. The later ones, including
you '03 are internally balanced, same as neutral balance. That part I know for
a fact.

The change was mid to end 00.