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

a-bodyguy said
I have one :)
68 340 orig rings bearings
refreshed top end weiand stealth 650dp unilite 218 218 454 110 in 106 3.91sg tf-2 727
102k on the bottom end 169 psi cranking compression

by all accounts, this is the same motor that you've raced, changed cams on and shot nitrous at?
*raises eyebrow*