Small Block Chevy Cast Iron Intake Manifold Dyno Charts

Can You Use Some Extra Horsepower?

A stock cast iron intake is the most restrictive item on a small-block Chevy racing engine. Let’s face facts: Stock cast iron intake manifolds were designed for passenger cars where the engine never sees 3,500 rpm. In a race application, the engine is never under 3,500 rpm. We have seen lap times reduced a couple tenths of a second with our Modified Cast Iron Intake Manifolds.

Horsepower Comparison 2 barrel Cast Iron Intakes

TEST ENGINE: 355, Stock ’492 heads, flat top pistons, flat tappet cam, headers and stock 500 Holley 2 barrel carb. NOTE: The intake manifolds were the only components changed.

“If you are running Hobby Stock, Limited Late Model, or Sportsman, you couldn’t miss hearing about Brzezinski because he is the prime exponent of having the stock cast iron intakes and heads pull more air than ever before.  He has learned all the good part numbers and the ways to make them respond.”

— Alex Walordy, “Cast-Iron Creativity” – Circle Track Magazine.

Horsepower Comparison 4 barrel Q-Jet Cast Iron Intakes

TEST ENGINE: 355, Stock ’492 heads, flat top pistons, flat tappet cam, headers and 750 Holley 4 barrel carb. NOTE: The intake manifolds were the only components changed.