4 Valve "B" heads

[jay87lx]

When people refer to "B" heads, what are they referring to? What are the differences between years?

[Turbov6Bryan]

When people refer to "B" heads, what are they referring to? What are the differences between years?

4 thread 03
9 thread 04
Spark plug holes

Just drill out the 03 heads and use what's called a time sert kit

http://www.timesert.com/html/ford_sparkplug_faq.html

[jay87lx]

So would B heads be '03, 4 thread holes?

[maximusslade]

Whoa!!!! Back up there pardner. DOHC "B" heads are heads from -98 Cobras and -98 Lincoln Mk VIIIs. What is the difference between them and say Marauder heads? LOTS. In practical sense 20ish horsepower in stock trim is my guess.

B heads 98 and lower DOHC

C heads 99 and 01 DOHC

03/04 heads are kinda sorta C heads, you can use C head intakes on them, but they flow a bit more than C heads do.

B heads use intakes that have IMRC.... Whatever that stands for, what it means is that there are valves between the throttle body and the actual combustion chamber. At lower RPM, one of the intake runners is close, creating increased flow velocity and therefore low end torque. Above like 3000 rpm the valve opens and increases flow rate which helps top end horsepower.

C heads don't have that crap.

For more details there are VOLUMES of info on various forums... google is your friend.

[dmjarosz]

IMRC = Intake Manifold Runner Control. I had it on my 99 SHO. The actuator cable was always breaking.

[maximusslade]

Why? You looking for some B heads? I got a pair. I've also a 96 Intake manifold with IMRC. I also have some 97 IMRC.

[jay87lx]

Why? You looking for some B heads? I got a pair. I've also a 96 Intake manifold with IMRC. I also have some 97 IMRC.
I found some for sale- was just wondering of they were anything special

[maximusslade]

NA, not so much. But if you plan on putting a super charger or turbo.... they would be hot stuff.

[Turbov6Bryan]

Whoa!!!! Back up there pardner. DOHC "B" heads are heads from -98 Cobras and -98 Lincoln Mk VIIIs. What is the difference between them and say Marauder heads? LOTS. In practical sense 20ish horsepower in stock trim is my guess.

B heads 98 and lower DOHC

C heads 99 and 01 DOHC

03/04 heads are kinda sorta C heads, you can use C head intakes on them, but they flow a bit more than C heads do.

B heads use intakes that have IMRC.... Whatever that stands for, what it means is that there are valves between the throttle body and the actual combustion chamber. At lower RPM, one of the intake runners is close, creating increased flow velocity and therefore low end torque. Above like 3000 rpm the valve opens and increases flow rate which helps top end horsepower.

C heads don't have that crap.

For more details there are VOLUMES of info on various forums... google is your friend.

I totally read 03 04 difference lol. My bad

So I was wondering,... You say 20 hp difference in HP between the old heads vs ours
Is that 20 hp in favor for the old ones? Is that because of the intake cams profile? I read that you can gain 10-20 hp by adding the older intake cams and degreeing them when putting them on the newer motors

I would have totally thought the newer 03-05 heads were better just by looking at the prices of the heads for sale

You know more about it than I do, I'm just asking :)
Thanks

[maximusslade]

I don't "know" more. I just did a lot of research for my 4V swap into my Crown Vic.

No the horsepower gain is in the newer head's favor. The issue with the B heads is that they flowed.... too well. The volume of airflow through B heads was high enough that the speed of the air was adversely effective. The end result of this was a serious lack of low end torque. Ford attempted to correct this by using IMRC valves. By constricting airflow to a single intake port below 3000 rpm they effectively increased the speed of the airflow (read venturi effect) and thus increase torque. Above 3000 rpm the other intake port opens up and you have more flow, which means more high end horse power.

C heads (or tumble port heads) changed things by controlling the air in such a way that instead of whirlpooling into the cylinder, it would instead become turbulent and slow down a bit.

Which one is better? Well it is never that simple. With things like different intakes, different cams, different tunes, it is all a mess.

But in stock form, the C head engines produced better torque and HP than the B head engines...... but...

Due to their high flow characteristics, if you are using forced induction, i.e. super or turbo chargers, ported and polished B heads are a great choice (with deleted IMRC valves) since they allow you to pack more air into a cylinder.


My original build was going to be a stock MkVIII engine and drop it in the Vic. Well fellows here and on CV.net told me to stop being dumb and use later heads with a cobra intake. Well, I partially heeded their advice, because I am on a budget, and did my own thing...

MK VIII shortblock Teksid for the win!
2001 Lincoln Continental heads (are the exact same heads and cams you will find in a 2001 Cobra)
2003 Marauder intake because... well... duh.

Many suggested I go with the 98 cobra intake cams since they have the longest duration. But they are expensive and hard to find. 2001 cams are the next longest intake duration and well... I got the heads for $100, with valve covers, cams... everything... junkyard finds are the best.

Talking to a few people about what kind of numbers I might be looking at... Guy I spoke to at Mo's says that with setup and a tune, I could be looking at 320... I am degreeing the cams and people say that could net me another 20. I am so far going with a stock 2.5" exhaust, but am considering a 3" Stainless Works exhaust, so that might be another 20 horses... or so they say.

[jay87lx]

There is a set for sale on my local CL so I figured I'd ask. $100

[maximusslade]

Unless you were going to put a supercharger on it, I'd stick with C heads or 03 heads.

[Zack]

The answer is B heads are no good