Porting the GT40 Intake

The GT40 intake manifold was available on 5.0 powered Ford Explorers, and it didn't take long for Mustang guys to figure out that it makes more power than the Mustang intake. It was a cheap improvement for my stock Mustang 5.0 but with the new heads and cam, it wasn't enough. I looked at some aftermarket intake manifolds and they are all so expensive. Then I stumbled upon a guy who claims to port GT40 intakes to make the same or more power than aftermarket intakes, with dozens of dyno graphs to prove it. His method of porting is written up here: How to port GT40 intake

I followed the directions and here are some pictures:

I took an intake gasket and glued it onto a new head

Then I used a die grinder to open the gasket up to match the port shape and size

I transfered the shape to the intake manifold

And opened it up with the die grinder. I did a bunch more smoothing out of the port after this picture was taken

Before

After