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.
1961-1966: Automatic Only. May Require ALT/GEN Bracket.
1973-1987: 2WD ONLY.
Header Style: Tri-Y
Header Material: Steel
Header Finish: Silver ceramic coated
Primary Tube Diameter (in): 1 5/8 in.
Collector Attachment: 3-bolt 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: No
Motor Mounts Included: No
Transmission Mount Included: No
Quantity: Sold as a pair.
Notes: Dual AIR injection fittings, one on each header.
Drivetrain 4WD
Power Steering Yes
Power Brakes Yes
Air Conditioning Yes
Standard Transmission Column Shift No
Standard Transmission Floor Shift No
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.
9 - May require alternator/generator bracket.
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.
Additional Information
| year make model | 1973-1987 Chevy Blazer 1961-1987 Chevy C/K Pickup 1963-1966 Chevy Suburban 1973-1987 GMC C/K Pickup and Jimmy thy300ydac |
|---|---|
| Manufacturer | DOUG THORLEY HEADERS |


