SKU: TRA9374
UPC: 086923093749
MPN: 9374
The TRANS-DAPT 9374 header reducers solve a common problem on a built engine: matching a 3-inch header collector to a 2-1/2-inch exhaust system. Sold as a pair, these reducers bolt to the collector and step the diameter down so you can run smaller-diameter pipe behind the headers without leaks or fabrication. They suit street and strip cars where the headers came with a 3-inch collector but the rest of the system runs 2-1/2-inch tubing. If you need clean flange-to-flange fitment between two pipe sizes, this is the part that bridges the gap.
These reducers are built from heavy gauge steel, with the large end measuring 3 inches and the small end 2-1/2 inches. The collector side uses a 3-inch floating ring with a 3-bolt (tri-bolt) flange, which lets the ring rotate to line up the bolt holes against your header collector flange. That floating design takes the guesswork out of clocking the bolt pattern, so you are not fighting alignment during install. The tri-bolt flange pattern matches standard 3-inch header collectors, and the gasket-style mating surface seals against a collector gasket. The aluminized steel construction holds up to exhaust heat. Pair these with the matching collector hardware and a 3-inch flange setup to complete the connection.
Reach for these reducers when your headers terminate in a 3-inch collector but the downstream system is sized at 2-1/2 inches. That mismatch is common when running mid-size mufflers or a tighter chassis routing that favors smaller pipe. Bolt the floating-ring end to the collector, weld or clamp the 2-1/2-inch end into your pipe, and you have a sealed transition. The tri-bolt flange makes future service simple since the system unbolts at the collector. Browse our full exhaust lineup for matching clamps, gaskets, and pipe reducers to finish the job.
These reducers connect a 3-inch header collector to a 2-1/2-inch exhaust system. The large end measures 3 inches with a tri-bolt flange and floating ring, while the small end measures 2-1/2 inches to mate with your pipe.
The 9374 kit ships as a pair, which covers both header collectors on a typical V8 dual-exhaust setup. Both reducers use the same 3-inch floating ring and 3-bolt flange pattern.
The 3-inch floating ring rotates freely on the reducer body so you can spin it to line up the three bolt holes against your collector flange. This removes the need to clock the bolt pattern precisely and makes install and future service easier.
They are built from heavy gauge aluminized steel, which resists exhaust heat and corrosion. The gasket-style mating surface seals against a standard collector gasket at the 3-bolt flange.
The 2-1/2-inch small end slips into or against your exhaust pipe and can be welded or clamped depending on your system. The 3-inch end bolts directly to the header collector using the tri-bolt flange and a collector gasket.
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