Mustang Cobra Engine vs. Mark VIII(8) Engine Quesiton

On the early mark VIII engines, the throttle body is near the fire wall. That should be a dead give away. If it says 'intech' I would be scared. I've only see that on the fwd 4v, which absolutely won't work for you.

I beleive you can use the cobra intakes on the mark 8 engine. I think you need the correct IRCM plates (is that what they are called?) and the cobra intake.

Far as I know, the rule of thumb for the forged crank, is the type of transmission the car origionally had. If it was an auto car (like the mark 8), then it got a cast crank. Unless you plan to make more than 600hp, it probably doesn't matter which crank you have though.

Other than the intake and crank, there really isn't much difference between the mark 8 and cobra engines. If you insist on a forged crank, you can have the owner take a picture of the back of the crank to verify that.

the number of bolts that hold the flex plate/ flywheel on.

cast is 6 bolts, forged is 8 bolts

There are plenty of 8 bolt cast cranks out there. 1999 and 2000 gt's have a Windsor pi 4.6 with an 8 bolt cast crank. It really doesn't matter though how many bolts they have. As far as the cast crank compared to the forged unit, it's more about rpm capability than load capacity. The forged unit is more stable as RPM increases due to the center counterweights. However, I have never even heard of a cast crank breaking. I ran a supercharged combo with 586 HP at the wheels at 7000 RPM with a cast crank. I figure that is roughly 850 HP that the crank is seeing when you account for drivetrain losses and the power used by the supercharger. The crank never had a problem.

Anyway, there are a couple of other differences with the engines. The intake manifold is different obviously. The camshafts are also unique to the mark VIII, they are set for more low end torque due to the extra weight of the mark VIII.