I have a fairly stock engine compartment that was neglected. In my process of cleaning it up a bit, I have been trying a variety of products to clean up the faded plastic wheel wells, plastic fan shroud, etc. Most products work for a short time, but fade again after a short time.

I'm trying Poorboys Trim Restore (http://www.poorboysworld.com/trim-restorer.htm). It seems to go on very easy and shines nice. I'll let you know how and if it lasts.
http://elcaminocentral.com/albums/album349/afterpoorboys1.jpg

http://elcaminocentral.com/albums/album349/afterpoorboys2.jpg

i would tape all your stuff up you dont want to get painted and paint it black again when we had the motor out of my car we painted everything gloss black we went and got a quart of gloss black and medium reducer speaking of it i still have some in my bedroom you mix the paint up and spray and it will look good i have had the paint on for about 4 months and it still looks good heres a pic if you look on the firewall you can see the glossy black its like that everywhere we painted http://i6.photobucket.com/albums/y214/81elcamino/708508_29_full.jpg

Your engine compartment looks great. Yep, if I had the engine out, I could really go to town. But for now, I'm trying to see how well I can do without repainting.
Plus, most of the engine compartment firewall, radiator support, and other metal look pretty good. It is the plastic fender wells and other plastic and rubber that I'm trying to "pretty" up. For whatever reason, on my '73, they used a lot of plastic in and around the engine compartment.

I'm really hoping this Poorboys Trim Restore holds up.

well then take them out and paint them or tape everything with tape and newspaper you dont want painted and paint