Most interchange and parts books list those C8OE-A and B numbers as GT heads. Well in real life they are the engineering numbers found on the C8AE-6090-H FE head blueprints. And yes the 14 bolt C8AE-6090-H are true GT heads. The same ol heads found on all other FE's from late 67 on till the D2 heads came along. Just the bolt pattern makes them correct for the GT application. And those can be drilled if they have a different bolt pattern. My 68 S code Cat's 390 is bone stock with 14 bolt C8-H heads. In fact the whole engine, smog, AC and all is original. And shares quite a few smog and AC parts with the 428CJ applications. As far as the heads having different bolt patterns for other applications I'm not exactly sure. But I'd think the original GT parts were 14 bolt only. All the ones I've had were that were original. And service replacement castings were all 16 bolt to cover all applications exhaust pattern wise. Thus one head fits all applications.



G.