Doug Thorley Headers THY-306Y1-C GM Class A Motorhome 1987-1994

Doug 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, Doug Thorley Headers 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.

Brand: Doug Thorley Headers

Manufacturer's Part Number: THY-306Y1-C

Part Type: Headers

Product Line: Exhaust

Header Style:     Tri-Y

Header Material:     Steel

Header Finish:     Ceramic coated

Primary Tube Diameter (in):     1 3/4 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:     No

Motor Mounts Included:     No

Transmission Mount Included:     No

Quantity:     SOLD AS A PAIR

Notes:     Fits models with TH400 transmissions.

Drivetrain     RWD

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:   

May require alternator/generator bracket.

For legality under CARB regulations, the included connector pipe must be used on vehicle originally equipped with a catalytic converter.

Will not fit column shift.

Vehicle Type Group     Automotive