Depending on which book you use you will see different settings. I use .012 on the intake and .016 on the exhaust when hot. Cold start up can be set .002 looser and reset when hot. The 477-412 and 819 heads have the small ports. Some 270's use the 417 large port head (rare) and the 302's all use the large port 983 heads. Gaskets will not interchange.
Joe
