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Hooker Cast Iron Exhaust Manifolds For LS Engine Swaps

By: Dan S05/03/2012 < Back to Blog Home
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Installing a set of Hooker LS Cast Iron Exhaust manifolds on a 1972 Chevy pickup with a 5.3L V-8 swap. 

LS engine swaps in early model cars and trucks are a popular upgrade that can provide excellent power, reliability, and improved fuel economy. While there are many aspects to performing an LS engine swap, one of the biggest decisions is how the exhaust will be routed from the engine to the rear of the vehicle. Holley Performance manufactures its line of Hooker LS Engine Swap Headers for a variety of early vehicle models, which solves many of these problems. Nevertheless, there are instances when a vehicle may be using a different frame, or have ground clearance issues, that can limit the use of long-tube headers. This is why Holley came out with its Hooker LS Cast Iron Exhaust manifolds. These are often a great solution for many LS engine swaps, because they can be used in a very wide range of unique and popular applications without any fitment problems. 

The Hooker exhaust manifolds fit any GM LS engine, except LS7 and LS9 ultra high performance models. The thicker exhaust port flanges eliminate any chance of leaking, and Holley offers these exhaust manifolds with a variety of high-temperature ceramic coatings that include black, cast iron gray, silver and titanium finishes. Or, if you want to paint the manifolds a custom color, they are also available in a raw finish. The manifolds are cast from hi-silicon, moly ductile iron that improves durability and has less resistance to corrosion. Shaped more like shorty headers, the cast iron exhaust manifolds have improved exhaust flow and can work with LS engines making up to 500 horsepower. The manifolds come with 304 grade stainless steel mating flanges and the 2.25 inch diameter outlet uses a two-bolt style flange, (the same as a 2010 Camaro), that makes a factory-style seal, and allows a muffler shop to easily bend a custom exhaust for your application. 

As demonstrated on an LS engine swap into a 1971 Chevy pickup, installation is simple and allows for a quieter operation and easy fitment around the chassis and engine mounts. In this application, the Hooker PN 8501-HKR exhaust manifolds with a bright silver ceramic coating were used. One of the first things you'll need to make sure you have on hand, is a set of factory exhaust manifold bolts, as none are included in the kit. If you don't have these, the GM Part number is 11518860 and you'll need 12 of them. You'll also need a set of exhaust manifold outlet studs (GM PN 11589264) and nuts (GM PN 15032594). The exhaust manifolds also do not come with the manifold outlet seals (GM PN 92202326), so you'll need to have those on hand as well. You can get more information on the installation by downloading a set of instructions HERE. Article and photography by: DS Media Relations


We installed a set of Hooker LS cast iron exhaust manifolds on this 1972 Chevy pickup, that was equipped with a 5.3L V-8 engine. 



The engine did not have the factory exhaust manifolds on it so we had to purchase a set of GM exhaust manifold bolts.



The Hooker cast iron exhaust manifolds came with stainless steel gaskets. These were inserted between the cylinder head and manifolds.



Use the original 12 GM bolts to secure the Holley exhaust manifolds to the engine. 




The Hooker LS exhaust manifolds feature a thick flange that will prevent any exhaust leaks and maintain a tight seal with the cylinder head. 



The passenger side exhaust manifold is also bolted into position in the same manner. 



Once the manifolds are in place and the bolts are tightened, the factory wires are attached to the coils and spark plugs. 



The driver's side exhaust manifold fits nicely within the frame and has plenty of clearance. A set of Holley LS Engine Swap Mounts can help position the engine mounts in the best position for the exhaust manifolds.



The passenger side also fits perfectly within the frame of this Chevy pickup with plenty of room between the manifold and the frame. 


The Hooker LS exhaust manifolds have a 2.25 inch diameter outlet that uses a two-bolt style flange, (the same as a 2010 Camaro).