Curious

Modern engines aren't all that special you add fuel injection roller cams overdrive and superchargers to anything. Yes we'll never have multiple displacement and variable cams.

That leaves heads where new engine shine. They basically come stock with what we would consider racing heads years ago (250-350 cfm).
They use head flow not large cams to make
Power that's why they get good mileage to hp and why aftermarket cams add so much power. We do it opposite with large cams and relatively weak heads. That's why 340 was a great engine its time better heads than the other guys. Thatso why it response so well to cam and headers like modern engines just on a lesser scale imagine if it came stock with W2 or W8 instead of X heads, that's basically how the new hemis and LS engine come.

To the OP you have the weight advantage probably need a 100 less hp to beat whatever Camaro.

440 with the new trick flows should more than do it :)

P.S. what's with this gas mileage crap the v6 Camaro only gets 18 - 28 not super impressive if you put a little thought and effort in your build you could get similar mileage to hp.