Stainless steel tubular exhaust manifolds are an alternative to the cast-iron factory manifolds. The tubular construction uses individual primary tubes from each cylinder port that merge into a collector at the manifold outlet, providing better gas flow than the cast-iron originals where exhaust gases travel through cast passages with relatively poor flow characteristics. The longer primary tube lengths also give some scavenging benefit at higher engine speeds.
Performance Benefit
On a standard 3528cc V8, the gain from stainless tubular manifolds is modest, perhaps a few percent peak power and an improvement in throttle response. The benefit grows with engine modification: a performance camshaft, performance heads, or capacity-upgrade engine all benefit more from the improved breathing offered by the tubular manifolds. They are typically chosen as part of a wider performance specification rather than as a stand-alone upgrade on a standard engine.
Construction
Stainless tubular manifolds are made from corrosion-resistant stainless alloy with welded construction. Service life is excellent, far longer than cast-iron manifolds in most operating conditions. The flange faces are machined for sealing to the cylinder heads using the same gaskets as the cast-iron originals.
Fitment
Tubular manifolds for the V8 are designed to fit within the standard MGB engine bay using the original cylinder head fixing pattern and the original downpipe connection. Some variants may require minor clearance work; the parts team can advise on specific fitment for the chosen manifold.
MGOC Spares
MGOC Spares supplies stainless steel tubular exhaust manifolds for the MGB GT V8, engineering staff are available to discuss fitment and specification.