On the subject of drag race cylinder heads, there’s considerable debate over which material—aluminum or cast iron—provides the ultimate power advantage. And on airflow test bench conducted by Hennessey the ported heads flow 360 cfm on every single intake port which is about 60 cfm much more than stock. The baseline power numbers are also down due to reduced compression (eight.five:1 vs. 9.6:1) compared with the other heads this was the only head tested with a 76cc combustion chamber, whilst the rest benefited from 64cc chambers. The Avenger heads are cast 356 aluminum, heat treated to T-six for strength and then CNC machined to precise tolerances. ATK’s New Casting Efficiency Aluminum Head, 70cc/210cc, 2.05/1.60 Valves, Hyd.
The design of the cylinder head is essential to the functionality and efficiency of the internal combustion engine, as the shape of the combustion chamber, inlet passages and ports (and to a lesser extent the exhaust) determines a key portion of the volumetric efficiency and compression ratio of the engine. For circle track engines, heads that provide excellent mid to high RPM throttle response and torque out of the corners will normally win more races than heads that deliver more peak RPM horsepower.
Trick Flow’s original High Port aluminum cylinder heads are arguably the castings that helped kick off the higher-functionality, small-block Ford head revolution. Far more flow throughout all valve lifts compared to out of the box Edelbrock heads with greater components installed for only a handful of dollars more!!!! Consequently, some aftermarket gasket makers now advocate a surface finish of 30 to 110 RA for cast iron head and block combinations, with a preferred variety of 60 to 100 RA for ideal final results.
By using a 1.84 intake and 1.500 exhaust valves, we achieved an average ratio of 75-79% at all valve lifts, thus generating our aluminum cylinder head well suited for naturally aspirated as well as boosted applications. Pro-Port Raw cylinder heads are specialty goal-engineered castings made for the expert cylinder head porter and engine builder. These differ somewhat in corrosiveness depending on the inhibitors of iron corrosion employed.
The factory Olds cylinder head uses a six-degree valve angle in an inline arrangement, and his selection to keep the new style to exactly where it would work for both street and race-kind applications presented lots of challenges. The V8 engine contains an equal number of cylinders positioned in a straight line on either side of the block. A head with 180 or 185cc intake runners will work nicely on a common 350 Chevy street engine that tends to make 400 to 450 horsepower.