Mark VIII 4v or 96 to 98 cobra 4v to build

[Black96vert]

Hey guys,

Trying to find another motor to build and boost to put in my 96 cobra. I am planning on keeping the motor currently in my car stock but going to forge the new motor. Some forum members have suggested me to go with a Mark VIII motor and put some C heads on it versus just getting another 96 to 98 cobra motor. I have a couple of questions concerning this.

How much more power will I gain by going this route.

Is it going to present more of a challenge to install.

I can already see that I may be able to get a Mark VIII motor cheaper than a cobra motor.

What would be the advantage of a Mark VIII with C head and KB vs. 96 to 98 cobra motor with procharger.

Sorry for all the questions just trying to make the right decision.

Thanks,

 

[96S/Cobra]

It will present no more of a challenge to install a Mark 8 engine vs. a 96-98 cobra engine into your car.

How much more power are you going to gain? There's no way to answer this, as there are too many different factors that goes into the final numbers produced by said combination.

You said in your post that you're going to forge the internals (crank, rods, pistons) in the new engine you build, which you will need to run any substantial amount of boost.

The Mark 8 engine and 96-98 cobra engines are very similar. The main difference is that the mark 8 engine has a 6 bolt cast crank, while the cobra engine has an 8 bolt forged crank. So getting a cobra engine will save you from having to buy a forged crank for your build. There are a few other differences, such as slight cam profile differences, intake, etc. but these are negligable considering you said you want to switch to c heads anyway if you get the mark engine. The blocks are the same, so either way you will be buying pistons and rods, and a crank if you get the mark 8 engine. So if you buy a mark 8 engine the only things you will be using (for the most part) is the block and front cover. All the internals will be replaced as well as the heads since you want to switch to c heads thus then being able to run an intercooled kb or whipple.

As far as a c headed kb/whipple car vs. a b headed procharger/vortech car, man that's like asking people which wheels look better on a car...everyone has their opinions on which set up is better. The pd blowers have tons of low end torque and make good power up top. The centri set up's don't make as much torque down low, but they pull like a freight train mid and upper rpm's. Some say the pd blowers are better for the street, and maybe that's true, but again that's a matter of opinion. I ran a kb on my car for 8 years, and I have since switched to a vortech. Each combination had it's up's and down's, but I truly think you will be pleased with whatever combo you decide to go with.

Just sit down and do the math. Which way is cheaper? Buying new heads vs. running b heads if you buy another 96-98 engine? But buying a mark 8 engine will be much cheaper up front, but again how much of it will you really be re-using? Finding a used kb/whipple set up vs. a used procharger/vortech set up, which is cheaper?

Good luck.

 

[KazooGS-T]

I would say talk with someone who has had a forged b-headed engine and then swapped to the c-heads with a KB/Whipple. There are a couple on this sub-section of the forum that have gone that exact route.

You will spend similar amounts, depending on which route you take. Why haven't you thought about doing a turbo setup, with an intercooler instead of a supercharger? Just curious..

You can take the whole mark viii engine, have the heads re-worked, do cams (with valve springs/retainers), forge the mark viii bottom end, and do a shortrunner intake and a ON3 turbo kit (sell the junky turbo they offer and do a decent turbo, garrett, turbonetics, even a holset) and have a SICK setup. You will actually come out around the same as doing a stock c-head swap, with a forged bottom end (there is a lot involved in doing that c-head swap, it's not hard, but can be expensive and very nit-picky for little parts) and KB.