I am about to put dual Ford 94 carbs on my 283 SBC. I have a healthy 292 Comp cam and produce only 5inch of vacuum. needing to know what power valve and jets I should start with to get them dialed in. does anyone run this set up?
Firstly you will need to know what 94's you have. there is approx 3-4 different sizes/versions, the biggest is the VW bug spray, they are around 300cfm, the most common off a 56 Ford are 185cfm, so 2 @ 185 = 370cfm so total useable would be about 320cfm. More knowledgeable 94 guy will chime in I am sure, I ran 3 off 94's for years only power valve in the primary (centre) carb.
In theory, - 5” of vacuum means you should have 2&1/2 pv (total) if fixed linkage. Playing with jet sizes and different positioning of pump linkage setting may be needed. Lots of threads on here about this. This one may help. https://www.jalopyjournal.com/forum/threads/multi-carb-question.54445/ 17 different ‘94 carbs. Although some question that figure. (I don’t think that the ‘56 as stated above is the most common one as that was ohv and probably 1&1/16 by then and I thought that the more common ones were ‘94s on the mighty flathead). I am still learning about them, but currently have two 1&1/16 on a 283 and it runs well with 51 jets and 3&1/2 pv - fixed linkage - (although not a lot better than a single with 57 jets and 7&1/2 pv), - original plan is to tip in a third (centre one). Most won’t do it that way. Plan b is run it off primary centre carb -57 jets and tip in outer two carbs which will make it similar to what I started with, 3 with fixed linkage and 57 jets, - scary....
https://www.jalopyjournal.com/forum/threads/links-to-holley-94-technical-info.286574/ some of this has been lost, but still a lot of helpful information here if the links open......
I didn't know there was so many 94 model's. when I pull them out of the carb dip i'll know for sure. one was stamped 59AB. probably off flat head i figure
both have a 15/16'' bore and ONE IS an 8BA . BOTH STAMPED FORD & 94. What else distinguishes them apart to know which ones I have?
I have a few 94's and the big difference right off is air horn design. Then you get down to the designs of the throttle levers and the ports for vacuum connections. I've yet to set them in line and decide if I have a pair that matches that I can run on the Offy intake on my flathead.
The theory is that if running fixed linkage, they must be the same, - identical. then they say leave both chokes in, but only one choke needs to work. (So that to me and my limited knowledge says that they are already different when the choke is on, and once the fuel is all mixing under vacuum doesn’t it all go together ?) I would think that you would want all the venturi sizes the same, as in don’t mix .94 with 1 or 1&1/16, 1&1/32 etc. Having said that, with progressive linkage, that is perfectly acceptable, in fact some of the experts on here like @C9 ( now deceased) have recommended this. disclaimer: my knowledge comes 100% from reading on the Hamb, and a little trial and error on a 283 sbc
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