Big-Block Exhaust
Increasing power and milage for a V-10

Text and Photos By: David Kennedy

   IN 1994 DODGE ENGINEERS DID THE unthinkable and gave us 488 cubic inches of V-10 power in ¾ - and 1-ton trucks to tow, haul, and kick 5.0L Mustang butt. This engine was developed for the Viper where the 360 V-8 wouldn't cut it, but earned its keep with truck owners who needed earthmoving torque without the turbodiesel price. But now just nine years after it was born it's the oldest big-block available in an American truck and we felt it was time to update the one guzzling gas in our stable.

There are two things every V-10 owner wants: more power and better fuel economy. In pursuit of both we decided that a new exhaust system for our truck was in order. We 488-ed our way down to MagnaFlow's Tech Center in Rancho Santa Margarita, California, to try out a new after-cat exhaust it has been developing to see if it would net us the more power/better fuel economy that we were after.

Knowing that "you can't hurt the torque curve" on these engines, MagnaFlow's director of product development, Mike Jones, ordered that a 4-inch stainless steel muffler and tailpipe combination be installed to permit deeper breathing for our V-10. The dyno charts show that we picked up power all across the rpm range, but the real story is in how much healthier the engine feels when you drive it. Gone is the annoying engine drone while cruising in high gear. In its place is an easier-revving, more powerful V-10 that's rewarded us with 1 mpg better fuel economy (at 10 mpg, every bit helps!) in a package that will last a lifetime.

MagnaFlow's new V-10 exhaust is based on its Cummins diesel system and uses a 4-inch inlet/outlet muffler and a 4-inch mandrel-bent tailpipe that are both made from stainless steel. The original factory exhaust has a 4-inch inlet muffler, but the muffler necks down with a 3-inch oulet and 3-inch tailpipe. Take a close look at the photo and you'll see how MagnaFlow reduced the huge rainbow bend the stock system needs to clear the Dana 80 axle to pick up a few extra ponies. This made possible because the compact design of the MagnaFlow muffler allows it to be mounted higher in the chassis than the original muffler.

MagnaFlow's secret to producing power isn't really a secret at all. Hot exhaust gasses flow straight through the muffler. There are no chambers, baffles, or restrictions to manipulate, slow, or restrict the exhaust from evacuating the engine. MagnaFlow doesn't need to interfere with the exhaust event to reduce noise because it has developed this perforated muffler core that skims the unwanted frequencies from the exhaust note and absorbs them in an exclusive stainless steel insulation that will not burn out.

Installing a MagnaFlow exhaust system is a breeze whether you're using a lift in MagnaFlow's state-of-the-art Tech Center like we did or on jackstands in your driveway. All the factory hanger locations are reused, and the new system is held in place with the original rubber isolators.

Double-check that the new exhaust clears the spare tire and rear shock and that you like where the 5-inch exhaust tip is positioned before you tighten any clamps or weld any joints. Welding is not required to install a MagnaFlow exhaust, but is a good idea if the vehicle will be subjected to severe poundings.

With a K&N air filter in the stock airbox, our 488ci V-10 made 247 hp and 386 lb-ft of torque at the rear wheels breathing through the factory exhaust. With the new MagnaFlow system installed those numbers jumped to 257 hp and 399 lb-ft. That's not a huge power increase when you look at it on paper, but it is enough that you'll be able to feel it every time you drive it. Additionally, fuel economy even improved another 1 mpg. Now that our V-10 has been alleviated from its asthmatic exhaust, it sounds more like its Viper sibling without picking up any loud or obnoxious habits.