Heads for 350 2-bbl Converted to 4-bbl

Q: Heads for 350 2-bbl converted to 4-bbl

A: With regard to the original post about cam selection for a 350 2-bbl converted to 4-bbl, I would suggest the Pontiac 067 or Summit 204/214 cam which was offered by someone on the list. I would go NO HIGHER than the 204/214 for your application, since you specifically wanted low end torque and gas milage. In fact I think the Summit 204/214 is probably a great bet for your needs.

A: Well put. Pontiac engines like a wide lobe center, in the region of 110 to 114 degrees. This will give you better idle characteristics compared to a cam with simular lift and duration, but with a tighter lobe center.

In addition, the port design in Pontiac heads favor low lift figures, which is why you see the factory cams with lift figures of .406″ (the exceptions are the “44” cam with .410″ and “041′ with .518”). Adding more lift is waste of time since the port design doesn’t flow any better at higher lifts.

It is said that Malcolm McKellar, an engineer at Pontiac in the 50s and 60s believed that higher lifts reduced the reliability of the engines with higher stresses on the valve train. He felt that lower lifts, along with port designs that favored efficiency at low speeds woul still make good power, but not at the price of valve train failure.

That, and the restricive exhaust ports demanded a balance between the intake and exhaust side.

As Steve suggests, either go with a Pontiac high performance grind, or an aftermarket cam that is very close. And read the Jim Hand information. He is the guru of Pontiacs, and he’s done all of the testing and experimentation for us.

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