[toddoky]

Originally Posted by Sieg

Doug's makes a 1-3/4" primary SAP-port part #D368 that I used with my AFR heads on my '69.

This appears to be the Gen 2 version. The SAP port design didn't create any interference on the AFR ports.

http://www.summitracing.com/parts/do...t/model/camaro

The folks at AFR were thinking clearly when they designed the large sealing surface into that cylinder head as it greatly helps minimize the sealing issues that arise when you put stock port headers on D-port GM heads. Because the machined sealing land is raised off of the cast surface of the heads and have a narrow margin, stock port design headers/gaskets commonly leak and/or blow out at the bottom of the ports. D-Port specific headers eliminate the leak/sealing issues on the GM L98/LT4/LT1 and Fastburn heads and also remove the step that forms at the top of the ports on those heads when stock port headers are used on them.