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New member needing insight

Jevans6

Member
Hello all. New member out of north Georgia needing some insight on a swap. 81 Notchback being swapped DOHC out of a 94 Mark VIII. What all is needed as far as setting up a cobra intake etc? And any measurements on where to cut the 96 subframe to fit the notch? What modules are required from the car to make everything work? Car is going a caged/empty interior. Fabricated dash and aftermarket gauges. Any and all help will be greatly appreciated
 

ndfastang

Active Member
I just did this but in a 63 Fairlane. My Mark VIII was a 94 like yours. The older Mark's came with aluminum IMRC plates that were vac operated by the solenoid at around 3000rpm and they went from 2 round(ish) ports on the intake side to the one round/one square ports of the B heads that are all the same. The Cobra (96-98) came with a composite IMRC plate that was electronically controlled by a setup that mounts under the intake. It is electronically controlled and it's ports are the same round/square as the heads so no transition.

You will need the intake of course and it's air charge tube (good luck finding that), The IMRC's from the Cobra unless you just do the delete from MMR like I did. Otherwise, you'll have to use a relay from the PCM to actuate the plates. I still have to tune around that but understand it's better off. The Mark TB was at the back of the intake versus the Cobra with the angled side mount. That calls for a longer throttle cable than the Mark. I just had to go through this part. You will NOT find a factory Cobra throttle cable at a dealership as they are not made anymore and you will NOT find one for a reasonable price on line anywhere even used. I think they are made of gold for what people want for them. I just made my own bracket and used a 24" build it yourself cable just like what Lokar sells, only cheaper and made my cable. The Mark IAC will not swap over. You need the rails from the Cobra intake, Spendy again. The injectors and MAF from the Mark will work just fine. You will need the EGR from the Cobra and you'll have to tap into your exhaust.

The Mark Alternator will work fine but you will need to cut off the stud excess on the back of the alternator. The Alternator upper bracket from the Cobra will be needed also. I made my own since I didn't need the coil wires going over it anymore. Grab the PCV setup if you can. I run breathers.

There are a few other little things you need to get at the store but that's the majority of it. The intake is made to rev higher than the Mark's springs in the heads in 94. I went with the Cobra heads with cams and valvetrain. You can use the Mark setup but if you have access tot he intake, maybe you have the head access too.

Here is a pic of my Mark Engine with the Cobra upper half......




Good luck with it!!!
 

Jevans6

Member
what would be required to delete the EGR? And what were the power gain? Is it worth the expense to do so or overall a better gain to just go supercharged on the system? Or would it be easier to just purchase an aftermarket performance intake upgrade with everything included for an easier swap?
 

ndfastang

Active Member
To delete the EGR, you just pull the valve assembly off and plug the holes in the exhaust and the intake. Then you have to disconnect the electronic part and disable it in the tune. As for HP gain? I don't think so. From what I've read, deleting actually hurts mpg but I have no visible proof of that yet and this is the first I've deleted it with. It's a 63 and in this state, it's not an issue. If I were going into a Fox, I think I'd keep it. I'm going for the minimal clean look here.

These engines are said to respond real well to boost due to the high flow characteristics of the heads. The problem is, your lower end(mine too) is limited to around 450-500hp. The crank is a 6 bolt but will still be fine. The rods and pistons are said to be the problem. I am getting mine running and setup to go and then pulling it all to paint the car and forge the bottom end this winter. There is only one aftermarket intake for these that I know of and it's stupid expensive and not usable down low in the RPM's. The MMR intake which is what the guy I bought my Cobra intake off of is using, he's going twins on his setup and will need it. The Cobra intake is had cheap enough and can be ported for good gains. I have 3/4" shorter runners in mine as well as port work and I run the MMR spacer and IMRC deletes and the Accufab 1200cfm single blade TB. That's plenty for a street or track car. There's no need to go more unless it's a dedicated high RPM track car. I almost picked up the newer Mark intake but it is said to be the worst flowing of all the intakes. Your Mark intake is great for torque and probably tops out at 5500rpm stock. Of course, boost changes that.

You really need to read up on what you want out of it. Look at my build and you'll see I change my mind......a lot! I've had a turbo setup, a nitrous setup and now a Vortech bracket on it for a blower and I just barely started it for the first time yesterday! I'm finally set on what I want and it cost me a bit to go through all that. Know your goal and search for the parts. If you can fab, you'll save tons.
 
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