my understanding from a mag. article is that they are 2 different castings. Heres a quote from the article.
The Victor Pontiac casting was designed to accept a traditional '65-'79 intake manifold, such as a Performer RPM or Victor. "In order to accomplish this, we raised the intake and exhaust ports by 5/8-inch and lengthened the intake port 5/8-inch on the 12.6-degree casting," says Garcia. "The 11-degree casting is raised and lengthened approximately 1.25 inches. The added intake-port length gives a tunnel-ram effect, which greatly influences airflow and performance. Either casting accepts conventional round-port headers."
Read more:
http://www.highperformancepontiac.co...#ixzz1eMeWixfb