I hate those ratings. It all depends on load, reciprocating and rotating weight, cylinder pressures etc. Its nearly useless

I would say that the stock block is your limit, and if the parts are decent aftermarket, and balanced properly, they should handle what you throw at it

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70 Sportsroof, 427 FE/489 cid, 10.7:1,Ported Edelbrock heads, and RPM intake, 1000 Holley HP, Ceramic Hooker Supercomps, TKO-600, 3.70, A/C