When installing performance headers, take a close look at your spark-plug wires. More than likely, they'll need to be replaced due to their age and condition. Since you'll have to remove the old plug wires and spark plugs to install the headers, it's the perfect time to drop in a new set.
Believe it or not, there are still quite a few unmolested 5.0 Mustangs running around. Just last week a friend of Associate Editor Johnson purchased an '89 notch with nothing more than aftermarket mufflers and the air silencer removed-proof that at least a few stock 5.0s still exist.
One of the first aftermarket products produced for the burgeoning 5.0 performance market was the short-tube header. Even though Mustangs wore tubular short-tube headers from the mid-'80s, the restrictions built into them for assembly-line convenience meant that an aftermarket variant could indeed improve on the factory offering. These headers were designed to replace the stockers with no modifications-something practically unheard of in the past, where long-tube headers replaced cast-iron manifolds and required extensive exhaust modifications to make everything work.
These days, replacement headers are a thriving business, with several manufacturers making variants of the original shorty header. Designs for applications range from 1 1/2-inch unequal-length headers to 1 3/4-inch stepped race headers, and several types in between.
For this story, we decided to go back to one of the originators in the field of short-tube headers and call upon JBA's line of Cat4Ward headers. We chose the company's Firecone 111/42-inch unequal-length, short-tube headers for our '85 GT as the car is going to see only a few bolt-ons and not any major induction mods such as cylinder heads. Swapping out the stock, crimped-tube headers (or the old rusty aftermarket ones that might have come on your Mustang from a previous owner) is a rite of passage for 5.0 owners. We'll show you how to do it.