First, soak the engine down good with degreaser at the car wash (have car running). Then hose the engine down good and try to get as much stuff off of there as you can. You'll have to get in there with a small brush (tooth brush works great) to get to the tight spots.
For the aluminum you will probably want to either take a wire wheel to these parts or sandblast them. Or, you could spend some time polishing them. It's a lot of work, but will be the best look you can get.
Then, use silicon spray on the plastic stuff, hoses and wires to make them look new again.
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Too much to list. Best ET on the car so far with stock 2.73 gears - 13.73@102mph
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