Hi,
The 1970 #15 heads have 1.96" intakes and 1.66" exhaust valves. It was rated at 360 hp in the 455 cid engine. They have pressed in rocker studs.
You can have the exhausts enlarged to 1.77" and put in hardened seats. I'm running a set on my 462 cid engine. My compression is 9.34:1.
Mike
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1968 Pontiac GTO 462CID, 4-Speed Manual, 3.55 rear. Aleutian Blue exterior, 219 Teal Blue interior. Chrome bumper, AM & 8-Track and Rally II Wheels
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