taking the 270 head is the way more bang for buck than a 240 if buying to replace other heads . On my 505ci motor i gained right @ 0.25 ET on my 440ci @ 0.20 give or take . These motors had been running CNC stealth head . I did have a Super Victor stock port that i opened up to max wedge . No other change to motors . Same intake , carb , rocker gear , cam , headers etc . This is a pump gas street exhaust motor .
The 440 went from 10.89 to 10.70 . With a 0.520 nett lift sft
The 505 went from 10.50 to 10.25 . With a 0.600 nett lift sft

Tex