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It's ambitious, and I hope you see some improvement. But honestly, no matter what you do, the only way you're going to get 40+ mpg from that car is to drive at 40mph on flat roads the entire time, with no stops or traffic.
I would NOT use a head with any cracks at all, you are bound to have a failure, especially as soon as you remove more material. There are some good articles on modifying this head (see the work that Mike Holler has done on it). It's all too easy to grind too thin in some spots and cause a crack. The reason these heads don't breathe well is that they are bulletproof, and drilling out too much or in the wrong areas can sacrifice life.
A K&N drop in filter is a total waste, as is one that is mounted out in the open underhood. So are the fancy wires and coil.
Your best investment would be to convert to a 5-speed for at least a 3-4 mpg gain guaranteed.
I would NOT use a head with any cracks at all, you are bound to have a failure, especially as soon as you remove more material. There are some good articles on modifying this head (see the work that Mike Holler has done on it). It's all too easy to grind too thin in some spots and cause a crack. The reason these heads don't breathe well is that they are bulletproof, and drilling out too much or in the wrong areas can sacrifice life.
A K&N drop in filter is a total waste, as is one that is mounted out in the open underhood. So are the fancy wires and coil.
Your best investment would be to convert to a 5-speed for at least a 3-4 mpg gain guaranteed.