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 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 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 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 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 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.