JBA 1650ST 2.5" SS Starter Tubes Header Reducers for 1965-1973 Mustang 289 302

Vehicle Fitment

• 1965-1973 Ford Mustang (289 cu. in. V8 / 4.7L)
• 1965-1973 Ford Mustang (302 cu. in. V8 / 4.9L)
• 1967-1973 Mercury Cougar (289 cu. in. V8 / 4.7L)
• 1967-1973 Mercury Cougar (302 cu. in. V8 / 4.9L)
• 1966-1973 Ford Fairlane / Torino (289/302 cu. in. V8, when equipped with JBA 1650S headers)
• 1966-1970 Ford Falcon (289/302 cu. in. V8, when equipped with JBA 1650S headers)

Fitment Notes

• The 1650ST starter tubes are designed specifically as a companion component to the JBA 1650S shorty header set. They connect the 1650S header collectors to the downstream exhaust system and are not a standalone header replacement.
• Tube diameter is 2.5 in., matching the collector outlet of the JBA 1650S headers. Verify that your downstream exhaust pipes accept a 2.5 in. inlet before ordering.
• Features a ball-and-socket connection style at the header collector end and a 2-bolt flange at the downstream connection for a secure, leak-resistant joint.
• Does not include O2 sensor bungs. If your application requires downstream O2 sensors, bungs will need to be welded in by a professional fabricator.
• Does not include bolts, studs, or gaskets. Hardware must be sourced separately.
• For 1965 model year vehicles, refer to JBA's 1650S fitment notes regarding motor mount requirements - 1966-1/2 and later style motor mounts (approximately 1 in. higher than 1965 and early 1966 style) are recommended for best fitment with the 1650S header system.
• Does not fit P-head (police interceptor) cylinder head applications - see JBA 1650S-2 header set for P-head fitment.
• Vehicles with a Z-bar clutch linkage may require Z-bar modification or the JBA replacement Z-bar (p/n 578-1650Z) for proper clearance.

Features

• Constructed from stainless steel for long-term corrosion resistance and durability in the high-temperature environment of a classic muscle car exhaust system.
• Ball-and-socket collector connection provides a self-centering, vibration-resistant joint that helps accommodate minor misalignment between the header collector and the downstream exhaust pipe, reducing the risk of leaks over time.
• 2-bolt flanged downstream connection provides a heavy-duty, serviceable joint that can be easily disconnected for exhaust system maintenance, header removal, or engine work.
• 2.5 in. diameter tubing matches the JBA 1650S collector outlet for a smooth, unrestricted transition from the header into the exhaust system, preserving the flow improvements achieved by the headers.
• Sold as a complete pair (left and right) to service both banks of the V8 engine simultaneously.
• Application-specific design ensures correct tube geometry and length for proper alignment with the JBA 1650S headers and the 1964.5-1973 Mustang/Cougar chassis without custom fabrication.

Specifications

• Part Number: 1650ST
• Component Type: Header Starter Tubes / Header Reducers
• Tube Diameter: 2.5 in.
• Collector Attachment Style: Ball and Socket
• Downstream Connection: 2-Bolt Flange
• Material: Stainless Steel
• O2 Sensor Bung Included: No
• Bolts / Studs Included: No
• Gaskets Included: No
• Compatible Header Set: JBA 1650S (289/302 Mustang/Cougar/Fairlane/Falcon Shorty Headers)
• Sold As: Pair (Left + Right)

Included Components

• 1x Left (Driver Side) Starter Tube - Stainless Steel
• 1x Right (Passenger Side) Starter Tube - Stainless Steel

Product Description

The JBA 1650ST is a pair of stainless steel starter tubes designed to bridge the JBA 1650S shorty header collectors to the downstream exhaust system on 1965-1973 Ford Mustangs and Mercury Cougars equipped with the 289 or 302 cubic inch V8. On classic Mustangs, the factory exhaust pickup point sits at a specific geometry relative to the header collector, and the 1650ST tubes are engineered to that exact relationship - eliminating the need for custom fabrication or one-off adapters when building out a complete JBA exhaust system on these applications. The 2.5 in. tube diameter matches the JBA 1650S collector outlet, ensuring a smooth, uninterrupted flow transition from the headers into the rest of the exhaust.

The ball-and-socket connection at the header end is a purpose-designed feature for this application. Classic muscle car exhaust systems are subject to significant thermal expansion, vibration, and minor chassis flex - all of which can work conventional slip-fit connections loose over time. The ball-and-socket joint self-centers and absorbs minor misalignment without stressing the joint, providing a more durable, leak-resistant connection than a simple slip joint. The 2-bolt flanged downstream end gives a secure, serviceably removable connection to the rest of the exhaust, making it straightforward to drop the exhaust for engine or header service.

The 1650ST tubes are sold as a pair and are intended for use exclusively with the JBA 1650S header set. They do not include O2 sensor bungs, bolts, or gaskets - these must be sourced separately based on your specific exhaust configuration. Builders using EFI conversions that require downstream O2 sensor placement should have bungs welded in by a qualified fabricator prior to installation. For P-head cylinder head applications, the JBA 1650S-2 header set is required in place of the standard 1650S.