TCCoA Forums banner

1 - 20 of 43 Posts

·
Registered
Joined
·
501 Posts
Discussion Starter #1
Hey guys... I will be beginning my DOHC build very soon. The engine is coming from 2 sources... One engine is from a 1995 Lincoln Mark VIII and the other engine is a 2003 Mach 1. Both are DOHC obviously, but I do not know what the differences are between the heads. The Mach's engine is blown... like hole in the side of the block blown, and I have not torn down yet to establish what is good and bad... there is a chance the head could be damaged I'm sure, but am not going to make any presumptions until I have it all torn down.

In the event the 03 heads are fine, I would like to make sure I choose to use the best head for the build.

Any wisdom on this is appreciated. Also, I am still learning my Fords, so if anyone might be able to shed some light on what the heads are, i.e. romeo heads, "B" heads and so forth... all of that is still a little Greek to me.

Thanks all
 

·
SuperNewbie
Joined
·
2,869 Posts
Here is some info passed ti me from another member. Hope this helps a bit.


-The "B" heads are on all 4.6DOHC motors from 93 to 98. This includes all mark 8 motors and all 96-98 mustang cobra motors. B heads are a split port design, and actually flow better than the later C heads, however don't make as much low end torque.
-The "C" heads, AKA tumble port heads, are on all 4.6DOHC motors from 99+ except for the 2000 Cobra R. The 03/04 cobra uses a slightly different version, however they are still the same basic design and intake manifolds will interchange between any 99+ DOHC. You can not swap intakes from a B-headed motor to a C-headed motor. For a street car, these are the best heads, however they cost a lot more, and the intakes generally cost more too, so they probably aren't worth the money.
-Cobra R/Aussie Heads. There was an entirely different head used on the 2000 Cobra R, and it is vastly superior to all the other heads. In america, the only way to get a set of these heads would be to show documentation that you own a cobra R, so they are pretty much un-obtainable. The only shot you would have at getting them would be through australia. The australian Boss 290 motor is essentially the exact same as the 2000 cobra R, but since they aren't a limited edition type thing over there, it would be possible to get them. Only problem would be having someone over there buy them and ship them over to you.
 

·
Registered
Joined
·
501 Posts
Discussion Starter #3
Here is some info passed ti me from another member. Hope this helps a bit.


-The "B" heads are on all 4.6DOHC motors from 93 to 98. This includes all mark 8 motors and all 96-98 mustang cobra motors. B heads are a split port design, and actually flow better than the later C heads, however don't make as much low end torque.
-The "C" heads, AKA tumble port heads, are on all 4.6DOHC motors from 99+ except for the 2000 Cobra R. The 03/04 cobra uses a slightly different version, however they are still the same basic design and intake manifolds will interchange between any 99+ DOHC. You can not swap intakes from a B-headed motor to a C-headed motor. For a street car, these are the best heads, however they cost a lot more, and the intakes generally cost more too, so they probably aren't worth the money.
QUOTE]

This almost seams to be a 6 in one hand and half dozen in the other type thing. The B heads flow "better" but at the cost of lower end torque. The "C" (99-04) heads don't flow as well, are more costly, but are considered the better choice for a street car.

Mine will be a street car, but it will have a kenny bell blower on board. For the blower, i am thinking flow would be better in one aspect, but then again with the blower in a less MAX 500 HP environment (at the crank, and that's IF I go with the stroker bottom end) I am thinking the blower is going to push enough air to comp for a nominal reduction in flow from the "C" head from the 03 Mach engine. Presuming the blower enhances torque along with HP the "C" head may be a better choice if I have the opportunity to use it from the 2nd engine I have.

This is a start, but I think I am going to still need additional info. Thank you for the input! :thumbsup:
 

·
The Parts Guy
Joined
·
7,306 Posts
Mercy,

You're going to want to go with the "C" heads if they are in good condition, as you'll be able to get an intercooled KB for those heads. KB doesn't offer an intercooled setup for the "B" heads.

The ideal setup would be an intercooled KB on the "B" heads.

Also, as a little additional info, a stroker "B" headed DOHC with a KB on top will make more than enough torque down low for the street. ;)

I'm working on answering your PM as we speak.

-Rod
 

·
Registered
Joined
·
7,758 Posts
Just my opinion, but I would recommend a big bore 5.0L, with P&P'd "B" heads, with the non-intercooled KB. (and sell the "C" heads to recoup the P&P prices).

I think dollar for dollar that is the best "bang for the buck", especially when you factor in how cheap the KB is for the non-intercooled DOHC's. :D

But again, just my .02. :thumbsup:
 

·
Registered
Joined
·
501 Posts
Discussion Starter #6
Mercy,

You're going to want to go with the "C" heads if they are in good condition, as you'll be able to get an intercooled KB for those heads. KB doesn't offer an intercooled setup for the "B" heads.

The ideal setup would be an intercooled KB on the "B" heads.

Also, as a little additional info, a stroker "B" headed DOHC with a KB on top will make more than enough torque down low for the street. ;)

I'm working on answering your PM as we speak.

-Rod

Rod, the PM you sent is a big help... you even touched on the fuel pump which I forgot to ask about. One of the reasons I was looking at the KB was because the twin screw design is said to deliver a cooler charge of air and does not "require" an intercooler. Is the intercooler going to a big deal if I am not going to exceed 10 pounds of boost?

From my research the 99 to 2001 DOHC cobra/mach 1 motors were cast bottoms with forged pistons, and in 03 to 04 the cobras had forged rods, cranks, and pistons. This is what I want to see is true once I break down the 03 mach 1 motor. Ideally, this will have a forged crank... and it is still good, which case I will just buy a set of rods and pistons, bore the block out and go that route. If it is not forged, or is damaged beyond recovery, I will surely go with the bottom end you did.

I am concerned to run an intercooler mostly because the 4.6 must be showhorned into the car as is. amything extra going into the engine bay is just not a welcome concept to me. The 2003 heads came with a 5.4L intake came in them, but I will not be using the ones in them anyway.

The 03 heads seem to be the direction I will go in, merely for upgrade potential. I do want to save money, but not at the expense of building myself into a box.

I may not build something as radical as your engine Rod, but do think it would be nice to have the potential in the future. The C heads seam to give me that room to play.
 

·
Registered
Joined
·
501 Posts
Discussion Starter #7
Just my opinion, but I would recommend a big bore 5.0L, with P&P'd "B" heads, with the non-intercooled KB. (and sell the "C" heads to recoup the P&P prices).

I think dollar for dollar that is the best "bang for the buck", especially when you factor in how cheap the KB is for the non-intercooled DOHC's. :D

But again, just my .02. :thumbsup:
I have 2 4.6 DOHC engines in the garage, and at the end of the day do not plan on building the car for the drag strip, however I do want to make the best choices for the parts I have gotten up to this point. I do like the 5.0 if nothing else, just because it is a more narrow engine. However, the Mark VIII engine was free and the Mach 1 engine was very cheap. This being the case I have minimal money invested and have plenty between the two to make a very nice power plant.

Yes, the DOHC engines are more expensive to build, but I have some goodies already and feel a little to commited to the 4.6 at this stage in the game to change the road I am on. Besides, I need to take the tranny into account as well. I am using a GM T-56 manual which will also be going into the car and I already have the info needed to mate that to the 4.6 and make that conversion happen also. I am sure there is a way to mount a GM T-56 behind a 302 and put it in the MN12, but I don't want to have to go back to the drawing board for that either.
 

·
Registered
Joined
·
7,758 Posts
I have 2 4.6 DOHC engines in the garage, and at the end of the day do not plan on building the car for the drag strip, however I do want to make the best choices for the parts I have gotten up to this point. I do like the 5.0 if nothing else, just because it is a more narrow engine. However, the Mark VIII engine was free and the Mach 1 engine was very cheap. This being the case I have minimal money invested and have plenty between the two to make a very nice power plant.

Yes, the DOHC engines are more expensive to build, but I have some goodies already and feel a little to commited to the 4.6 at this stage in the game to change the road I am on. Besides, I need to take the tranny into account as well. I am using a GM T-56 manual which will also be going into the car and I already have the info needed to mate that to the 4.6 and make that conversion happen also. I am sure there is a way to mount a GM T-56 behind a 302 and put it in the MN12, but I don't want to have to go back to the drawing board for that either.
The 5.0L I was refering to is the "big bore" DOHC. It's still the 4.6L modular engine, just punched out (via new cylinder sleeves) to make it a 5.0L. :thumbsup:
 

·
Registered
Joined
·
501 Posts
Discussion Starter #9
The 5.0L I was refering to is the "big bore" DOHC. It's still the 4.6L modular engine, just punched out (via new cylinder sleeves) to make it a 5.0L. :thumbsup:
Aaaaahhhhhh... I will need to look into that than... especially if I am going to be buying pistons anyway! Thanks for the tip.
 

·
The Parts Guy
Joined
·
7,306 Posts
Well, here's a little info on the 5.0L stroker "B" head setup with the KB 2.1L non-intercooled:

In 94 degree weather, spinning the blower to 12,700 rpm (should make 8 psi on an average 5.0L engine), I'm seeing 5 to 5.5 lbs of boost. The air charge temp reaches 178-180 at the end of a WOT run from a dead stop to the top of third gear (a 1/4 mile run). Average crusing ACT's are right around 140 degrees in mid-90 degree weather. From my point of view, that air is getting pretty warm. For my situation, I'm either going to install methanol injection, or figure out a way to build in a liquid-to-air IC under the blower, before upping the boost.

Mercy, the KB intercooler for the "C" heads is a liquid to air IC built into the blower manifold. It isn't going to occupy any additional space in the engine compartment, though you would need to install a heat exchanger in front of the radiator. I'd recommend the intercooled "C" head kit, as I believe it will best match your goals. But like I said, running the "B" heads certainly isn't the end of the world. It just requires a little additional work to cool the air, but the "B" heads will outflow the "C" heads any day of the week.

-Rod
 

·
Registered
Joined
·
369 Posts
03-04 Mach 1 with auto trans have cast cranks and 5-speed have forged cranks.If I was you I would keep the 03 mach I heads because they are great for N/A and boosted application .You can go cheaper way and get 03-04 cobra blower set up.
 

·
The Parts Guy
Joined
·
7,306 Posts
Also, the choice between big-bore and stroker really depends on your situation. If you have to bore the sleeves anyway, it doesn't cost all that much more to step up to a big-bore. In my case, the cylinders were perfect (only 3,401 miles on the engine), but the rotating assembly was trashed. Going to a forged stroker rotating assembly cost me a grand total of $100 more over a stock stroke forged rotating assembly...and the crazy torque increase is very nice. ;)

-Rod
 

·
Registered
Joined
·
369 Posts
the "B" heads will outflow the "C" heads any day of the week.

-Rod
They will outflow the C heads 99-01 but they won't outflow the 03-04 cobra heads stock for stock.03-04 cobra heads are great for boost applications because they have very good exhaust flow.
 

·
The Parts Guy
Joined
·
7,306 Posts
I have that book as well...I won't get into what I think of SHM.

Yes, stock for stock a '03-04 Cobra head will outflow a "B" head at high lift. However, the area under the curve is very close between the two, as the "B" head will flow better at lower lift on the exhaust side. Either way, it's negligible, especially when you do a little work to the heads, swap cams, etc.

I probably should have mentioned the FR500 heads, too.

-Rod
 

·
Registered
Joined
·
501 Posts
Discussion Starter #17
How about this... Yaw'll rock! This info is perfect! And might i add I aposted the same question on a mustang specific site and got absolutely DOOT in reply!

Ok, as I am processing all this info...

Between stroked and/or big bore, I am thinking I would probably not want to do both. Rod, it sounds like your bottom end (Quick note... just saying that makes me feel dirty), is the best way to go. I remember you saying the stoker set up was only 100 bucks more. I am expecting to find a trashed piston and rod, and who knows what the crank will turn up with. In the event that the crank is hosed it is going to be the stroker kit hands down. If the crank is good (and forged) I will see about the prices on a foreged set of pistons and stronger rods only.
I am hoping the bore is ok. I haven't priced boring an engine that needs to be sleeved, but I'd rather not need to go down that road.

As far as the heads go... these are the from an 03. From what you guys are saying the 03 C heads to B heads flow differences is splitting hairs. The chance to add the IC that is contained in the intake sounds to be the ticket to me all day long. So now you guys have me hoping the heads are good.

Rod, I am sure I will probably impose a PM once I break this puppy down and see what I am messing with.

Thanks all! Thank you so much!
 

·
Registered
Joined
·
172 Posts
I used to own a Mach 1. The Mach 1 was just a little different than the 02 Cobra's from what I was always told. I'm currently putting my Mach 1 motor into my 95 Thunderbird. So here is some info I got from the Mach 1 Registry that I thought might be useful.
"Commonly known by Mach 1 owners as an "R" code DOHC, (for the unique VIN engine R code) this all-aluminium engine features the same high flow heads as the 2003-04 SVT Cobras, Australian Boss 260/290, Lincoln Aviator and Mercury Marauders, but has intake cams drawn from Ford's 5.4 Liter "Triton" V-8 to provide better low end torque. While on paper the 305 horsepower seems a loss when compared to the 1999 & 2001 SVT Cobras of a similar engine running 320hp(239kW), in practice the motor produced nearly identical power with more torque, some 320 claimed lb/ft, occurring at a much lower 4,000 rpms.
Likewise, the Mach 1 had 10.1:1 compression as compared to the 99 & 02 Cobra's 9.85:1 and the Mach 1 had an aluminium block unique from the SVT aluminium blocks. The Mach 1 also featured the high redline of 6,800 rpms and fuel cut off at 7,000."
 

·
Registered
Joined
·
333 Posts
vegeta1181, are you the guy that "Had" a beautiful Azure Blue MachI until a Ford stealership worked on your car and messed up something on the rear axle (bolt came loose) causing you to wreck the Mach??
 

·
Registered
Joined
·
172 Posts
vegeta1181, are you the guy that "Had" a beautiful Azure Blue MachI until a Ford stealership worked on your car and messed up something on the rear axle (bolt came loose) causing you to wreck the Mach??
Yes, that was my car. The right control arm broke. At least I was able to keep the engine and get all my money back. It should be fun driving around in my Mach 1 powered Thunderbird.:D
 
1 - 20 of 43 Posts
Top