No matter the condition of your 1974 Bonneville, OPGI has the Header Accessories you need to boost performance and get you back on the road. We currently carry 36 Header Accessories to choose from for your 1974 Bonneville, and our Price Match Guaranteed prices range from as little as $11.49 up to $1,479.99. OPGI offers Thermo-Tec plus five other trusted brands of Header Accessories for your 1974 Bonneville, to help you find quality parts you can rely on. With OPGI's 45-day return policy and thousands of customer reviews, you can shop with the utmost confidence. Enjoy parts delivered directly to your home, or visit our sunny Southern California Showroom & Warehouse to check out our Header Accessories in person.