camshaft for mild 340

j.d.duggan said

nm9 all I,ve found on the 915-j-1.88 heads say there 65cc and I would think they were surficed,I didn,t cc them but they had good clean face.

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The 65 cc is probably an NHRA spec. What that means is that 65 cc is the minimum combustion chamber volume which these heads can have after modification and still be competition legal; in other words, it is a competition spec, not a production head spec. The production chambers have been repeatedly measured and come out in the 70-73 cc range with consistency. Having a clean face may or may not mean they have been milled. So until these are cc'd, you really don't know what you have.

This is why the advertised 10.5 static CR for the early 340's is not the reality in most cases; it is based on some minimum production or NHRA head chamber spec, not typical production heads.