I FINALLY got cracking on my mid-engined V-8 Corvair. I'll warn you guys now: I'm planning Corvette ZR-1 power for this bad boy!
Starting with a body from the "Prestige" release of the AMT 1969 Corvair Monza coupe kit, I removed the Monza emblems to clean it up a little and the side marker lights to backdate the body to a 1966 model. I used masking tape to show me where to scribe the cuts for the radiator air outlet, using the back of an X-Acto blade (I used this older body because it's molded in a harder plastic than the more recent one from about 2006. That one is in the newer AMT gray plastic that I find more difficult to do bodywork on):

Now that the outlet is cut in and bent down, I've taped out the cutline for scribing the horizontal cut for widening the fenders. I warped the plastic in the outlet by using too much heat when bending it down, but it isn't so bad that I can't putty it back into shape. Once that's done, I'll install the sides of the outlet:

I scribed the horizontal line with the back of an X-Acto blade, then cut vertically from the center of the wheel arches to meet the horizontal cut with a razor saw. Then I carefully bent the plastic out to the new shape I wanted. First I bent it outward from the ends, then back in at the wheel arches. That left a small gap in the middle, but that will be easy to patch up later on:

Here I show the filler pieces that go at the top of the horizontal cuts. These are basically just to give the fenders form; they won't be visible in the final build:

Here the filler pieces are installed and sanded down to conform to the new shape I want for the sides of the car:

More filler pieces. These will go between the fillers that I put on in the last step and the tops of the fenders. they are curved top and bottom and chamfered from behind to be mounted at the correct angle to blend in with the body:

This makes what I was describing above a little more clear. I didn't want a flared fender look for this one; I thought a widened fender look would fit the lines of the Corvair body better:

And finally, I cut off the front pan to mount a custom spoiler, made from a section of the custom nosepiece from the kit. It will eventually have an air intake in the center and covered driving lights beneath the stock headlight location. Those headlights will have flush covers too. Finally, the spoiler will have a aero splitter at the bottom to keep as much air as possible from going under the car and direct it through the radiator. Also, the car will have a full belly pan, and I'm even thinking about building in a ground effect tunnel in back!