detonation / knock issue on 340

ir3333 said
180 psi is too high for 91 octane with LA iron heads.
Get another carb and go back to post #10

I have 180-190 CCP in my street 340 with ported X heads. Run 91 octane no ethanol fuel all day crz'n - no issues
Custom ignition 34* of timing all in at 2700 rpm plus 10 * of added vacuum advance.