Details
Thorley headers are designed to outflow your stock exhaust manifolds. These headers increase gas mileage and give your engine more horsepower across the entire rpm range. The Tri-Y configuration builds the most power in the middle rpm range, which is great for towing and steep grades. To make these headers last, Thorley made them out of durable 14-gauge mild steel with 3/8 in. thick flanges and 5/16 in. collector rings. To prevent leaks, these headers have an O-ring welded into the flange, in addition to the high-temperature gasket provided. Unless otherwise noted, these headers are designed to fit the vehicle as it came from the manufacturer. This includes components like cylinder heads, chassis, steering, motor mounts, body mounts and bushings, etc. If your vehicle is using aftermarket components, parts from other applications, or custom altered parts, then it is the installer's responsibility to verify fitment.
Header Style: Tri-Y
Header Material: Steel
Header Finish: Silver ceramic coated
Primary Tube Diameter (in): 1 5/8 in.
Collector Attachment: Stock flange
Collector Diameter: 2.500 in.
Tuned: No
Primary Tube Gauge: 14-gauge
Flange Style: Standard
Flange Thickness (in): 3/8 in.
Bolts/Studs Included: Yes
Gaskets Included: Yes
Reducers Included: No
Y-Pipe Included: Yes
Motor Mounts Included: No
Transmission Mount Included: No
Quantity: Sold as a kit.
Notes: Includes smog ports.
Drivetrain 4WD
Power Steering Yes
Power Brakes Yes
Air Conditioning Yes
Standard Transmission Column Shift Yes
Standard Transmission Floor Shift Yes
Automatic Transmission Column Shift Yes
Automatic Transmission Floor Shift Yes
Application Footnotes:
2 - Will fit with angle plug heads.
3 - This Thorley header is available from stock with metallic ceramic coating by adding a "-C" to the part number. However, all Thorley headers can be coated--call for price and availability.
6 - This header is available with standard 1/4 in. air injection fittings by adding an "-S" to the part number.
10 - Will require air conditioning bracket on models equipped with "long" style compressor (1988 and earlier). Specify A/C compressor mounting location. L/S bracket P/N 8506. R/S Bracket P/N 8506.
15 - This header is available with fittings to accommodate models with dual air injection pumps. These use 7/16 in. -18 fittings. This was installed on some 1984-1992 small blocks and 1985-1989 big blocks. To order, add a "-DA" to the end of the part number.
17 - For legality under CARB regulations, the included connector pipe must be used on vehicle originally equipped with a catalytic converter.
21 - Fits vehicles originally equipped with a heat riser. Comes with replacement heat riser.
Additional Information
| year make model | 1973-1987 Chevy Truck and GMC Truck 1973-1991 Chevy Suburban and GMC Suburban thy364y4sc |
|---|---|
| Manufacturer | DOUG THORLEY HEADERS |
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