4v swap

[07GtS197]

So the 3v idea might be a little too expensive and not worth it in general so Ive put more thought into a 4v swap. When I had my 00 gt I contemplated doing the swap but the main deterrent was the lack of intakes and how expensive they were. Well I looked more into the mark 8 intake and the consensus is that its not that bad and it has longer runners than the B head cobra intake so the torque loss wont be as bad. I already have 3.73s and dont want to swap them for 4.10s or 4.56s so I dont want to lose that much torque. Would a mark 8 motor with the gen 2 mark 8 intake be a good compromise of low end torque and power output? I know the mark has different intake cams so swapping them out for 96-98 cobra cams will net some power. And the mark 8 makes peak torque at 4500rpm from the factory so it would peak at about the same time as the pi 2v but itll peak higher and have more hp. Plus that setup would be street friendly since I wouldnt have to wind it out past 6k rpms to make peak power like the cobra lol. What do you guys think about my blabbering?

 

[Nighttrain]

The 3v breaths way more than a 4v. Theres gotta be a wrecked 3v gt or f150 around. Anyway, blak made a thread on bheads and the way they are underplayed. Imo the only down side is the lack of a roots which im a big fan of.

 

[07GtS197]

I like the 3v a lot but imo its a waste unless you go with a big cam and/or retain vct. And then you still have the same flaws the 4v heads have like lack of low end torque. I wanted to swap in a 3v with the frpp control pack to retain all the oem functions like vct and adaptive spark but its a lot of work for the gain. For 1000 bucks I would swap in a 4v with longtubes and a tune and be at 300rwhp whereas Id be at 2k or so with the frpp kit and 3v. And dont forget moving the battery to fit the intake under the hood unless I custom make one.

Im not looking to use a 3v with the cams locked out and convert it to a cable driven throttle body, imo it makes a 3v swap a moot point. Yea they make 305hp from the factory and respond well to bolt ons but without vct and locking the cams either fully advanced or retarded, youre missing out especially under the curve which makes it a waste on the street. Like I said I love 3v's but it just doesnt seem worth it.

 

[Nighttrain]

I like the 3v a lot but imo its a waste unless you go with a big cam and/or retain vct. And then you still have the same flaws the 4v heads have like lack of low end torque. I wanted to swap in a 3v with the frpp control pack to retain all the oem functions like vct and adaptive spark but its a lot of work for the gain. For 1000 bucks I would swap in a 4v with longtubes and a tune and be at 300rwhp whereas Id be at 2k or so with the frpp kit and 3v. And dont forget moving the battery to fit the intake under the hood unless I custom make one.

Im not looking to use a 3v with the cams locked out and convert it to a cable driven throttle body, imo it makes a 3v swap a moot point. Yea they make 305hp from the factory and respond well to bolt ons but without vct and locking the cams either fully advanced or retarded, youre missing out especially under the curve which makes it a waste on the street. Like I said I love 3v's but it just doesnt seem worth it.

I got ya.

 

[07GtS197]

Any opinions about using the mark 8 intake?

 

[96blak54]

Yup

It works!...lol

 

[Nighttrain]

Hey blak, is there adapter plates or a roots made for b heads?

 

[96blak54]

Yea...I do believe there are Bhead to C intake adapters and vise versa. Or maybe its just Chead to Bintake....I cant remember. Something like that was available at one time.

Available roots s/c for Bheads? Not that I know of.

 

[Magic]

Yea...I do believe there are Bhead to C intake adapters and vise versa. Or maybe its just Chead to Bintake....I cant remember. Something like that was available at one time.

Available roots s/c for Bheads? Not that I know of.

There is the Kenne Bell kits for the B head 4v. However, not intercooled.

If I was doing a 4v swap, I would consider the C head 4v engines (99-01 Cobra, Mach 1, Marauder, Aviator) if you can get them reasonably.

 

[96blak54]

I dodnt know kenne bell went to great lengths for a B head modular. Very interesting! Can you score some pictures?

Why do you choose C heads over B heads?

 

[Nighttrain]

I dodnt know kenne bell went to great lengths for a B head modular. Very interesting! Can you score some pictures?

Why do you choose C heads over B heads?

Probably like most, you have to consider more parts availability and bolt on power adders, aftermarket performance and such. Thats why i would lean that way even with my ability to make my own stuff. Come on man! Its Murica! We want it and we want it now!

 

[96blak54]

This is true!

 

[07GtS197]

That is a downside of having b heads but I dont see boost in the near future and I dont see the intakes too often. Then when they do pop up people want a fortune for them usually lol. Do you think its possible to run in the 12s with a full bolt on mark 8 motor with upper and lower control arms and a 5 speed? Maybe slicks if I could justify buying a set lol.

 

[96blak54]

I can see a cobra B head long block doing 12's. I say that because of its intake. The Mark8 intake was for an automatic, but honestly I dont know what the mark8 intake will do. Im thinking their are 2 styles of mark8 intakes. One is tubes and the other is cast. The tube one is the most restricted and most plentiful.

Would you be willing to tinker with the engine before installing?

 

[07GtS197]

Yea one looks like the cobra intake and the other is completely different, sort of like the early 2v cast intake and the throttle body is mounted by the firewall. The mark 8 makes peak hp at 5500 rpms and peak tq at 4500 rpms so it does make peak power at a usable street oriented rpm. Thats the appeal for me, with cobra intake cams and full bolt ons it should make over 300-320rwhp, steep gears wont be necessary and the powerband is lower and more street friendly.

I would like to tinker with one but I dont think Ill be getting a new motor soon. What would you want me to do?

 

[96blak54]

Retard the exhaust cam a few teeth. Buy new lashers. Run 0w-20oil and get a cobra oil pump.

I have a mark8 intake on my parts shelf. Its made of round tubes....#1 power restriction! And its rear entry, but your right, effective power range for the street. I searched pics of the other intake and its definitely a better design with rectangular runners and can be ported. It has a side entrance which is a plus!

 

[07GtS197]

Hmm sounds interesting. What would retarding the exhaust cams do? As far as oil Im not sure if it would be ok to run that viscosity here in Florida but what do I know. All Ive ever ran is 5w-20 and sae 50 lol. Do people actually swap to that rear entry intake? That thing looks awful lol. Id use the one with the throttle body mounted on the side. My theory is that itll flow similarly to the cobra intake but Ive read it has longer runners so thatll make up for the torquelessness of the b heads lol.

 

[96blak54]

Scratch the oil. Run 5w-20. Still gotta get the cobra oil pump

I remember the mark8 craze and even the lincoln continental movement. These guys always sourced out cobra intakes and swapped to them. I cant see the rear entry intake being a top end performance intake. Visibly looking at it screems idle and driving quality, but hey if its all you got...run it. We will start there! Swapping to better components adds to the fun of the build!

About the exhaust cam retard. Ill see if I can explain good.

Think of the piston going down the bore just after the explosion. The exhaust cam starts applying pressure. Depending on compression in the cylinder depends on the degree of valve movement. Once the valve cracks open, the exhaust explodes out. ....hang with me here. Since there are 2 exhaust valves in this chamber....exhaust evacuation really isnt a concern. What I mean is.....if only one exhaust valve ....there would need to be a period of bleed down the exhaust would need....in other words more time to evacuate.

With 2 valves and an exhaust port my foot can step in.....no bleed down time nesassary. Their for....open the exhaust valve late as possible.

Instead of stock opening which is like 20° before piston reaches bottom dead center (not 100% on actual measures, dont hold me to it), move the exhaust opening when the piston starts to come up on exhaust stroke. This way the long stroke, long rod of a modular can utilize every bit of that compression. Utilize every bit of 2 exhaust valves.

On the flip side of retarding the exhaust cam will give you equally the same amount of overlap. We know overlap cams work well in conjunction with headers. Headers scavenge the exhaust while pulling in fresh air when both intake and exhaust are overlapping at the same time. AND! A tighter lobe separation angle. Which is like 116° stock (u can hold me to this one).

Clocking the cam one tooth is 8.5° at the cam but at the crank its double. That makes it 17° retard. Take the direction the exhaust cam rotates and counterclock them one tooth. Making the lobe late for the party!

Pair this trick up with cobra intake cams and new lashers, party gets fun!

 

[07GtS197]

That will be an interesting experiment. Ill see what I can get. Im going to start the police academy in January 2017 so I cant spend a lot of money right now. On a side note, I wonder how B heads would do on a 5.4 block with a decked block to up the compression slightly. My theory is that itll allow the 5.4 to breathe better than the C or gt500 heads.

 

[96blak54]

That will be an interesting experiment. Ill see what I can get. Im going to start the police academy in January 2017 so I cant spend a lot of money right now. On a side note, I wonder how B heads would do on a 5.4 block with a decked block to up the compression slightly. My theory is that itll allow the 5.4 to breathe better than the C or gt500 heads.

Its an experiment thats been done alot. I essentially explained a 100°LSA camshaft with undocumented overlap. (This reminds, I need to map out a set of mark8 cams). This is the beauty of seperate intake and exhaust cams. You find a good running long block and ill walk you through it.

B heads on a 5.4l would be a super trick idea! Stock form could rock some great power numbers.