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Part 3: Engine Swapping 101Sometimes an engine that's longer isn't quite as good as one that's wider From the August, 2002 issue of Mopar Muscle By Randy Bolig Photography by Randy Bolig
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With 170 cubic inches, it... With 170 cubic inches, it was dependable, but a powerhouse it wasn't. It was a simple idea. The '67 Valiant we introduced last month ran fine, but the reliable 170-inch Slant Six that was given residence between the front tires just wasn't what I had in mind. Sure, these engines can be built to produce some respectable numbers on the dyno, but not without some serious mods, and let's not even mention the difference in the sound. So, in this next installment of Project Valiant Effort, we investigated some things you may want to consider if giving your six-powered ride two more cylinders. There are different ways to accomplish this--the way the engine gets mounted, the suspension, and even cooling needs can be covered in a variety of ways. Hopefully, we can give beginners some information and perhaps add to the knowledge of the more experienced. In the end, we want to make this thing run well and keep it together long enough to make a pass or two at the track.  (A) A friend told us he had...  (A) A friend told us he had a '71 360 he would sell. When we got to hishouse, he also had another 360 and an 83/4 rear from an A-Body he threwin with the deal. Not bad for 250 bucks, eh? A nice thing about buying acomplete motor is that usually all the bracketry and pulleys you needare already on the motor. This saves expense and the time spent tryingto find the miscellaneous items.  (B) Ron thought the engine...  (B) Ron thought the engine had fairlylow mileage, so a quick inspection of the plugs and bearing surfacesshowed good indications. With high hopes, we cleaned and painted theengine and brackets and installed a spare Edelbrock Performer intakethat came with it. We topped all this off with a Holley HP 650 carb andCrane 25 ohm wires. The HP series carb may cost a little more than astandard 650 but will stay with the engine longer during our upgrades.  To physically mount the V8...  To physically mount the V8 where the six was, either change the K-frameto a V8 unit or do what we did and get Schumacher Creative Services'swap kit. The kit came with the motor mounts, tranny mount, and allnecessary hardware. We also got their new torque strap kit, which goesfrom a motor-mount bolt to a bracket that mounts to the K-frame.  The exhaust can be tackled...  The exhaust can be tackled by buying those quiet A-Body V8 manifolds orgoing the easy route like we did we did--headers. We chose Hedman Hedderswith a 15/8-inch tube into a 3-inch collector. The Hedmans are coatedinside and out, and for performance you can't beat a good set ofheaders: Hedman also sent us a crossover tube, which helps performancethrough a scavenging effect. Regardless, the six's skimpy exhaust wasn'tgoing to cut it.  To mount the tranny to the...  To mount the tranny to the motor, the bellhousings are different. In thecase of our Valiant, we didn't want a three-speed tranny for obviousreasons. So we bought a 23-spline 833 tranny from a friend for $200.Since we needed a bellhousing, another friend sold us a Lakewood safetybell for $40. It may be heavier than the factory unit, but keeping theflywheel from coming up through the floor like a buzz saw seemed kind ofimportant. It pays to ask what your buddies have sitting in theirgarages while doing this type of stuff.  The six-cylinder engine uses...  The six-cylinder engine uses a longer throttle cable than the V8 unitand will need to be changed accordingly. You can find one at a swapmeet, salvage yard, or through the street-rod aftermarket.  A lot of guys who drag race...  A lot of guys who drag race use the six-cylinder torsion bars because they react faster with the added weight of a V8.  However, they don't corner...  However, they don't corner at any real speed. If you plan to drive your car a lot, upgrade to a V8 bar to support the added weight under driving conditions such as potholes, roadwork, and the occasional Dukes of Hazzard imitation.  Swapping to a V8 also means...  Swapping to a V8 also means you need to address the cooling system. Thestandard six-cylinder radiator (right) was in rough shape, but the V8requires more cooling anyhow. We contacted U.S. Radiator and got one oftheir V8 replacement units with the special "optima core" (left). Sincethe Valiant will serve double-duty and eventually receive even moreperformance,we needed a radiator to handle the task both now and downthe road. In essence, buying it once is better that having to buyanother one later.  Another often-overlooked area...  Another often-overlooked area is the wiring. The Slant Six starter is onthe drivers' side near the top of the motor. On a V8, it's underneath.Tip: Some wiring modifications, like lengthening and rerouting, will berequired; have the tools or a harness to do this.  Our car had the small 71/4...  Our car had the small 71/4 rear, by no means able to handle what we wereabout to throw at it. Like I said before, we got lucky with an 83/4spanner along with our engine, and after we install our built-742 casedifferential, it will be fine. The price of upgrading to an 83/4(especially in an A-Body) is climbing, especially if you want the larger41/2-inch bolt pattern axles, so plan accordingly. While you cancompromise with the 81/4 under some circumstances, the 83/4 remains therear of choice for most non-Hemi street cars.  When going to a V8, there...  When going to a V8, there will be more stress on the driveshaft. If youplan to really launch your car hard, especially with a four-speed, westrongly recommend getting the sturdier V8 driveshaft; you can eitherhave one made or locate one from a V8 car. Under normaltransportation-only type driving, the smaller one would probably workfine, but who of us does that? Also keep in mind that Mopar offered twodifferent size universal joints: the 7260 is the smaller unit, while the7290 is larger and more durable; these need to be strong. Finally, ifyou are using an automatic with a fairly stock converter; this will be alittle more forgiving since it's a "fluid coupling system" instead of adirect gear. The verdict: Better safe then sorry; upgrade to thestronger styles as soon as you can. Grab One More: New Five-Speed Tranny
If you've decided that a four-speed just isn't quite what you want, Keisler Automotive has the answer. Keisler five-speed tranny is the result of hundreds of hours of design, prototyping, testing, and manufacturing efforts from engineers, machinists, and automotive component specialists. In fact, special patent-pending technology was developed in-house to achieve the final product. This intense effort provides you the opportunity to affordably implement one of the biggest improvements to your car possible. The conversion kit starts with a TREMEC TKO transmission, which is then modified by Keisler Automotive for your specific Mopar application. All companion parts are supplied, each specifically designed for the appropriate application. The engineered Keisler five-speed for Mopar kit provides you with easy installation and years of trouble-free enjoyment. This is not a Borg Warner T-5, that lighter duty five-speed that Brand X utilizes; it's made for guys like us who grab gears.
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