These heads have the largest, as cast, GM production iron head ports. In the neighborhood of 325 intake runners. They need to have the rocker stud bosses tapped to 7/16 for regular BBC guide plates.

The stock 2.19 intake valves tend to be very heavy. Replace with aftermkt stainless. These are 119 cc. chamber and will direct bolt to Mark V and VI blocks.

Port erea is a bit much for a street motor. Great for a race motor. I have sold several sets and no complaints in the horsepower dept.

 

325? yikes