No matter the condition of your 1978 Bonneville, OPGI has the Smog Components you need to boost performance and get you back on the road. We currently carry one Smog Components to choose from for your 1978 Bonneville, and our Price Match Guaranteed prices range from as little as $36.99 up to $36.99. OPGI offers RESTOPARTS plus minus one other trusted brands of Smog Components for your 1978 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 Smog Components in person.