Compression test??

dumb question,,,what is the 302 head i see people talking about ???
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im guessing small valve,,hardened seats ??

ide stick with a 600 on the 273,,the smaller the cfm,,the crisper the botttom end,,,bigger cfm,,,more top end,,,but too much cfm can really hurt the over all peroformance,,of A 650 MAX with vacuum secondarys