You can tell a lot about a Ford from the body tag located inside the driver-side doorjamb if you have the factory service manuals. I didn't, so I had to buy a set off eBay for $120. Now I know that my truck has a C6 transmission (Trans code: K), a Ford 9-inch rear with a limited slip and 3.50 gears (Axle code: H6), and the front Dana 44 with the optional limited-slip differential (Axle suffix code: 2). Truthfully, I could've figured all of that out by making a few phone calls, but I needed an excuse to buy the manuals.
Budget Left: $980

I was surprised to find a two-barrel 351W V-8 under the hood instead of the more common 302. Thanks to California smog laws you could only get the HO 351 four-barrel engine in the other 49 states. Not that I'm complaining, mind you. I replaced the $59 air pump (it seized) and installed the Bosch spark plugs the previous owner left in a NAPA bag on the front seat. I never got around to changing the oil, but I should since there was a new Fram filter in the bag with the spark plugs. As you read this I'm probably still working on replumbing all those vacuum lines for the emissions system. And I'm a little worried about why there was a spare radiator in the back seat when I bought the truck....
Budget Left: $921

The main reason I got a Bronco for the Cheap Truck Challenge is the fact that they come with a lot of desirable parts, even for a Chevy guy like me. Because my Bronco has the optional 351 engine, it left the factory with the 1-ton-tested C6 transmission and a rare Ford-spec NP208 transfer case. Most GM truck owners swap their 208s out for the older NP205 to get rid of the factory slip yoke, but Ford owners can enjoy the 208's lower gearing (2.61:1 low-range versus 1.96:1 of the 205) because they came with a fixed-yoke rear output shaft. I also like how the Ford 208 is clocked up to be level with the framerail. I wish my Blazer's transfer case was like that.
Budget Left: $921

This must have been one of the last Ford 9-inch axles ever made. The 3.50 gear and limited-slip differential in mine aren't that impressive, but the 31-spline shafts have proven strong enough for 35-inch tires. The same can't be said for the tailpipe, which unfortunately snapped off behind the last hanger. Now the exhaust likes to collect under the truck when idling, and work its way into the cab while driving. A $53 tailpipe from AutoZone should solve both problems.
Budget Left: $868
Another exhaust-related problem came from one of the catalytic converters (A). Over time the excessive heat caused the rubber radius-arm bushing (B) to deteriorate on the passenger side of the truck till there was metal-on-metal contact. Not good! Ford must have figured this out after my Bronco was built because later-model trucks come with a $10 heatshield that I can add (Ford PN E4TZ-3B463-A) to keep this from happening.