305 heads question.

[Hotrodcort]

Yeah, they're the 267-305 CID heads. Not sure witch one they came from. I know for sure that the 305 heads have higher compression to compensate for the smaller pistons. Bone stock 305's in early 80's K5 blazers came with 9:1 compression. Valves were small though. To my knowledge, 1.84 was the largest intake valve available. But any machine shop can remedy that. I have a set of 601's and the search shows 58cc, 1.84/1.50. Just can't seem to find cc size for the 450 heads.