421 Stroker with Trick Flow Heads/Intake Dyno - Redux

70dart340 said

Thank You for posting, it's helping to nudge my rudder in the right direction. I'm building a similar 408. Did you have any detonation on 92 octane with 11.0-1 compression? I was planning on 10.5-1, but if I can run 11.0-1, I'll do that. I appreciate you sharing this build with us. Paul.

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You're very welcome. Happy to help.

Negative. No detonation at all. I used VP pump 92 Non-ethanol for the dyno. I cut and inspected every plug afterwards and we didn't find any specks on the porcelain using a magnifying glass. Plugs were gapped at .035

Depending upon the local fuel quality in your area you should be fine at 11:1. A word of caution is to do the math and get your true C/R. The online calculators do a good job to get you within a range, but if you really want to to know for sure, take the measurements and do the math. I've been off as much as .75 C/R before on other motors.

Good luck!