[jdean]

My understanding is that the Edelbrock heads use stock intake port sizes, not SCJ. Intake port volume is about 10% more than stock type, but I forget exact volume numbers.

They are designed as a performance street head, not a racing head, and are supposedly good for up to 600 HP. A recent Car Craft article featured a pump gas 460 making about 628 HP with Edelbrock heads. This was just a 466, not a 514 or 545.

The real difference in the Edelbrock as opposed to stock heads is in the exhaust port. Flows much better.

Many "stock" 460 heads (non CJ) are decent performance heads if time is spent straightening up the exhaust ports. The main issue with them is that they are very heavy.