From Racer X:
The Racer X Fabrication 304 Stainless steel top mount exhaust manifold was created from customer request. The 304 Stainless steel exhaust manifold uses thicker pipe instead of tube to withstand the higher temperatures. The pipe diameter is matched to the common valve sizes used on the 3SGTE engine, and primary lengths that are optimized for power and quick spool. The 304 Stainless steel manifold is a great fit for builds on a bit more of a budget but still want power and durability.