Looking for exhaust manifolds for my 113 heads. NOT headers ! I need quiet.
What exhaust manifolds bolt up to the D port heads ?
Can I port my OEM manifolds ?

 

Driver side exhaust manifold from a LT1 4th gen and passenger side manifold from a LT1 4th gen.

Drivers side needs to be from a 93/94 50 State emissions car or a 95 49 State Federal emissions car. Must be 3 bolt ball and socket type outlet flange.

Passenger side needs to be a 94 50 State emissions car or a 95 49 State Federal emissions car. Must be 3 bolt ball and socket type outlet flange.

The 95 California emissions cars have a dual cat exhaust system with these huge weird exhaust manifold outlet flanges that the cat convertor bolts directly to on the driver side and a flat flange on the passenger side that won't work for what you are wanting. Same for any 96/97 car.


93/95 & 94/95 F-Body LT1 exhaust manifolds with 3 bolt ball and socket exhaust outlet flanges. Heatshields removed.

Heatshields installed.

Crusty used LT1 Exhaust Manifolds.

 

Those look like my 1996 Impala SS exhaust manifolds.

 

They more or less are. This style of cast iron exhaust manifold was used on the 1993 to 1997 F-body (Camaro and Firebird), 1994 to 1996 B-body (Buick Roadmaster, Chevrolet Caprice, and Chevrolet Impala SS), and 1994 to 1996 D-body (Cadillac Fleetwood) with the L99 4.3L V8 and LT1/LT4 5.7L V8 engines. Horsepower ranged from 200 HP to 330 HP with this style cast iron manifold with most 1997 SLP LT4 6 speed powered Camaro SS and Formula Firehawks putting about 325 HP to the rear wheels. This style manifold was also used in circle track racing and other types of racing where a factory cast iron manifold was required and the rules allowed.

The D-port cast iron manifolds I mentioned in my first reply are the only factory production ones I know of that can even come close to meeting your requirements and fitting into your car with some modifications. They also flow like gangbusters for a factory cast iron manifold. Way better than the log manifolds in our 3rd gen F-body cars that were designed for a 5.0L engine from the ground up and tacked onto a L98 as an afterthought. These LT1 style cast iron manifolds were designed from the ground up for a 5.7L engine and flow like it. You can just look at a TPI log manifold vs a LT1 manifold and know which one flows better.

B-body L99/LT1 cars have an additional front passenger side heatshield that F-body cars don't have. This heatshield can be added to the F-body manifold.