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Doug Thorley Headers 309-C

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Headers, Shorty, Steel, Ceramic Coated, Chevy, GMC, Pickup, SUV, 4.8, 5.3L, Pair

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  • Order this item and get free delivery and handling on your entire order! Offer excludes truck freight fees. Valid on orders shipped in the contiguous United States.

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Brand: Doug Thorley Headers

Manufacturer's Part Number: 309-C

Part Type: Headers

Product Line: Doug Thorley Headers

Summit Racing Part Number: DTE-309-C

Header Style: Shorty

Header Material: Steel

Header Finish: Silver ceramic coated

Weld-Up: No

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

Cross Over Pipe Included: No

Catalytic Converter(s) Included: No

Motor Mounts Included: No

Transmission Mount Included: No

Quantity: Sold as a pair.

In-Store Pickup: Choose In-store pick-up (OH, GA, NV) on our web site.

Backed by 40-plus years of knowledge and experience, 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. Their design configuration builds the most power across the rpm range, which is great for everything from street/strip performance, to towing, to 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 and topped them off with a good looking, nickel chrome plated finish. 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.

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Most Helpful Reviews Review this Product

4 Customer Reviews for Doug Thorley Headers 309-C - Doug Thorley Headers

Average Customer Review

5 Star

(3)

4 Star

(1)

3 Star

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doug thorley headers

Summit RacingSummit Racing Verified Purchase

The directions that I received are VERY POOR. They do not tell you that you have to drop the exhaust in order to remove the drivers side manifold and install the header, as for the right side ,the instructions are correct but that's the only side they give instructions for. As for the headers they did improve the performance of my truck. I have seen an increase in my fuel mileage also when towing my 31ft. travel trailer. ...read more

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Reviewer: LEONARD from PA

Date: October 12, 2014

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Price/Value
Quality

Well made headers and fit my swap perfectly

Summit RacingSummit Racing Verified Purchase

I purchased these headers for a 72 K20 LS swap with motor moved forward 2" and a hydraulic clutch. I had to clearance the drivers side frame rail a bit, but otherwise they fit great, are very stout and have factory type flanges/gaskets.

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Reviewer: CHRIS from MD

Date: July 17, 2014

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headers

Summit RacingSummit Racing Verified Purchase

Really happy with the purchase and performance of my headers

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Reviewer: LEONARDO from CA

Date: June 16, 2014

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Great Product

Summit RacingSummit Racing Verified Purchase

Great design and welded professionally. If using on a stock crossover, buy new gaskets and don't use the ones in the kit.

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Reviewer: CALEB from WY

Date: March 26, 2014

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Some parts are not legal for sale or use in California on any pollution-controlled motor vehicles

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