holley carb mystery
I purchased a 73 mach 1 last year. 351 4v w/ 4 bolt mains, 4 speed. has a holley 4160 carb. ran the numbers by holley to see what is was, and got a surprise. they told me they supplied this carb to ford in 72 and 73, for use on 351 engines. 605 cfm. I have never heard of a holley being used from factory in 73, and my ford factory repair manual does not show it anywhere [ I have complete set of 1973 ford repair manuals, still in the box it was shipped in, with a postmark of march 74] does anyone have any info on this?
also, the only vin code it shows for 351 4v is Q, and the factory manual lists it as a CJ, which I believe is the only place ford refers to this engine as a cobra jet. the question arises in the cam and head spec charts. there is a CJ cam listed, and also an HO cam, which has more intake lift, and while the compression ratio is listed at 8:1 for both, the HO combustion chamber volume is listed as being smaller. I can't seem to find any other info anywhere on this HO listing. anyone have any clues? i'm wondering if such an engine exists, or if Ford changed their mind after manual was printed. the service spec supplement, printed July 73, does not mention any HO engine. i'm curious more than anything, I don't intend to tear the motor down at this time, just wondering how much weirdness I may or may not have.