8. The key to our 454’s output of over 700 hp are CNC-machined intake ports that flow an impressive 343 cfm at .700-inch lift despite retaining that stock 20-degree inline valve configuration. Just as importantly, by .300-inch lift they’re already flowing 222 cfm. Although 240cc intake ports may seem a tad small for a max-effort 454ci motor, with port dimensions measuring 1.310 by 2.300 inches, the cross-sectional area of the High-Port 240 heads is actually larger than the port on Trick Flow’s 250cc 18-degree small-block Chevy castings (1.350 x 2.200). Simply put, the High-Port castings flow more air than their port volume suggests.