The 335 series engines used different cylinder heads for two and four barrel carburetors. The 2V (two venturi) small port cylinder heads were used on 2-barrel engines while the 4V (four venturi) large port cylinder heads were used on the 4-barrel engines. While the 2Vs used the smaller port of the two, these ports and valves were significantly larger than Windsor engines. The 4V heads had enormous ports which flowed very well, in particular at higher valve lift. The 4V heads could out-flow Chevrolet Double Hump heads and Chrysler's high-performance 340 heads. 2V heads still have excellent flow, and actually have slightly better flow than the 4V heads at lower valve lift values.