How to get 400 hp out of 1971 340 .30 over

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Taking my 69 340 to the Dyno in a couple of months.
Just curious what everyone thinks since we are on the topic.
TRW flat tops 10.5:1
X heads
RPM Air Gap
Holley fuel pump
Holley 670 DP
TTI Headers
FBO Ignition
This is just going to be an engine dyno. Car is not ready yet.
I’ll post Dyno sheet when it’s done to see how close everyone is.
Thanks in advance.
420/445