1.12 venturi? That's a new one on me. As far as I know there was the 1.08 and the 1.21 that came with the introduction of the 1968 351 and 390 series engines. If I am wrong, please correct me.BornInAFord said:4100s were phased out throughout the 67-68 model year in favor of the 4300, IIRC. 4100s are good carbs (Mid and I both have one... ) but not original for the 351. If it's a 1.12 venturi, it may be big enough. A 1.08 will probably be marginal at ~480CFM.