Back in my college days I used to have a real problem. Not with the Dean's daughter or with my GPA. I was hooked on junkyards. For some reason, whenever I got the chance I'd hit the self-serve junkyards, pay my $1 entry, and wander the aisles of cars and trucks. To me, it was better entertainment than any movie or playing golf.
However, where there were once rows upon rows of big-block Mopar 383s, Chevy 1/2-, 3/4-, and 1-ton pickups, motorhomes housing rebuildable 454s or 460s, and Q-jets cluttering the ground, something changed. All of a sudden, I started seeing injected 5.0L Cougars, 305 TPI Camaros and Firebirds, and scores and scores of 4.0L XJs. It seems the digital, injected world was wearing out. All the better for us. Here are some killer parts for your Jeep that should be at a junkyard near you.
Dana 300
Look for the Dana 300 in '80-up CJs as a great replacement to the earlier Spicer 18 and Dana 20 T-cases. You'll need a different adapter when swapping from an 18 or 20, and the rear shaft should be upgraded to a 32-spline output, but the front should be OK as long as you're not feeding it stupid amounts of horsepower or driveline bind.
Ford Taurus Electric Fan
Our resident electronics weirdo, Associate Editor Trasborg, claims the electric fan out of a V-6 Ford Taurus is able to cool mild V-8s in a single bound. Apparently, you'll need to rig up a relay and thermally actuated on/off switch, but otherwise it's a cheap alternative to a spendy aftermarket unit.
Carbureted Chevy V-8Still the staple, just about any Chevy V-8 will up the power of your Jeep. Go on half-price day and you can nab a complete engine from carb to pan with all the accessories for around $90. Look for engines out of mid-'70s pickups and wagons because they were commonly four-bolt mains. To verify a four-bolt main block, check for the casting number (3932388) on the flat portion of the block on the driver side behind the cylinder head. | 
SM465 AdapterIf you're looking to swap a four-speed into your rig and are running or want to run a 32-spline input T-case, look for an SM465 out of an '80-'88 GM four-wheel drive truck. These trannies have the same six-bolt round adapter bolt pattern as the NP, NV, Dana 300, and Atlas transfer cases and 32-spine shaft as some Atlas and the left-hand drop GM NV231 and 241 T-cases. The only drawback is the adapter (left) is about 7 inches long. | 
Overdrive 18It's not often you stumble across a Warn or early Saturn overdrive, but it does happen. This is the second Spicer 18 we've seen with the coveted range box. Look for them in early Scouts, CJs, Willys trucks, and flatties. The tipoff is the four shifters sticking up through the floor. You should also start looking for Spicer 18s because they're bound to start getting rare. A good, non-rebuilt overdrive fetches around $400 to $500, while a decent Spicer 18 can get $150. The junkyard wanted $95 for the bellhousing, T-90, T-case, and overdrive because it's just a manual transmission to them. |
'99-up 4.0L IntakeEarlier 4.0L engines used a more squared-off, log-style intake manifold that hampered flow to the outer ports, especially the #1 and #6 cylinders. Beginning in '99 Chrysler employed this horseshoe-shaped, high-flow manifold with individual runners. It's said to be worth anywhere from 10hp to 25hp over the log-type manifold. You may need to convert to the later power steering brackets and move a few vacuum lines, but the manifold bolts to all 4.0L engines. You can also use this manifold as a way of converting from the earlier Renix-style injection. | 
Disc Brakes For Early AxlesStarting in '77, CJs got front disc brakes from the factory. If you find a '77-'78 CJ in the junkyard, you can pull the entire brake system off the front Dana 30 and bolt it on to a Dana 25 or Dana 27 with just a little grinding on the older closed knuckle for clearance. Or you could use Chevy 11/42- or 31/44-ton calipers and caliper brackets, the 111/48-inch thick rotors for a '77-'78 CJ, and the stock Jeep hub assembly as outlined in "The Top 25 Tech Questions" (Mar. '06). | 
XJ Gas PedalIf you're building your own buggy, retrofitting an older CJ, or are just sick of the way your floor-mounted pedal feels, nab a firewall-mounted pedal out of an XJ or MJ. They bolt on easily, and the throttle cable is usually a perfect match for an early Jeep with a V-6 or V-8. |