Looks good, truck sounds like a real hot rod!!
As for the photos, I like your choice of light metering, very cool!! Looks good with the backrounds and subject. not much colour but you make up for it with the drama of the sharp shadows and contrast.
on the second shot, I would personally move the camera to the right so that the space is in front of the truck. Just sort of a convention and looks best in most shots. Also place the truck so that those vents are not in the shot. either behind the truck or just not there. Cleaner shot with that cement wall being a defined texture like that. Oh and turn the trucks wheel slightly right so that the tread of the tire is partially facing the camera. Gives the shot more visual stability. I know the way you have it presents the wheel square on to the viewer, but its a bit far away to get the full effect of the wheel anyways.
on the 4th one, crop a bunch of that concrete at the bottom of the photo and all of that yellowish space above the buildings.
Then again, I am not a pro, and there are some guys on here with more experience than me, so you may get more helpful advice from them. And if you like your shots, thats what its about at this point.
If you sign up for a flickr acount, there are lots of good newbie groups with many world class pros to critique your work. its really helpful and a years pro membership is $15 or something. Unlimited uploads, lots of help, well organized.
