.Those heads are smogger heads, designed for fuel economy, and emissions compliance. Just like the 307 itself, they aren't performance pieces by any stretch of the imagination. They have 74cc chambers, and give your 307 a very low compression ratio of roundabout 8:1. Make no mistake, the thing will run with those heads on it, but for a few bucks...say maybe $400 or so, you could be in much better shape with a different set of heads.
Your engine would have been very very very very lazy with that 292 cam in an 8:1 307.
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