Porting the Exhaust
Manifold
While having the exhaust manifold, and turbocharger off, I decided
to attempt to port match the exhaust manifold to the head ports, and
the exhaust manifold to turbocharger ports. I decided that attempting
to grind at the head couldn't be done very well while the head was in
the car. To measure the port sizes, I took a piece of cardboard,
cut out holes for the exhaust manifold studs, and bolted it to the exhaust
manifold. Then, took a sharp knife and cut holes into the paper
where the exhaust manifold ports are. I then unbolted the paper
and bolted it to the head. It turns out that the head ports (at
least on my 1991 MR2) were slightly smaller than the exhaust ports. That
being the case, I decided to port match the exhaust manifold to the gasket. As
can be seen in the following picture, there is a good bit of lip from
the gasket to the exhaust manifold. It would be best to also grind
the head ports to match the exhaust manifold gasket so that the ports
on the head match the exhaust manifold ports as best as possible.
By using an old exhaust manifold gasket, a die grinder (air tool from Lowes $20.00),
and some grinding stones from Sears, I ground
the lip off of the exhaust manifold to match the gasket.
I did the same with the turbocharger to exhaust manifold ports. Here
I used an old gasket to match both the exhaust manifold and the turbocharger
ports to the gasket. I put rags into the turbocharger inlet ports to prevent
dust from entering, and then used a shop vac to remove the dust. In the
following picture one of the exhaust manifold to turbocharger ports (left) has
been ground, the other (right) hasn't. You can see the significant lip
on the right hand port. Without the gasket:
With
the gasket: 
Both sides matched to gasket:
I then ground the turbo side.
With
the gasket: 
