my father & I are working on a 66 fairlane project & he has decided to use a tri power setup that he owns on the car. the car ran pretty well with the tri power on a 428 until he over-revved it & scattered the bottom end. while putting kits in the carbs, he noticed that the setup has 3 holley 4412's on it which I think are the 500 cfm ones. the two end ones have had the power valve replaced with a brass plug from the back side of the metering block. the rear carb had 68 jets in it, the front & middle have 73's. it has home-made progressive linkage. the manifold is a oe dual-plane ford. the motor is a .030 over 410....am checking on the compression ratio & specs for the hyd cam that the motor was built with. we are trying to come up with a good baseline jet setup & powervalve for both the middle carb & both end carbs. the car lives in portland, or which is pretty close to sea level methinks. any advice on baseline setups for this combo would be appreciated....
I don't have anything to help you, and a '66 Failane is starting to get O/T for the HAMB, but you may get some better info from the Ford FE Forum. Search that site as there is a number of FE tripowers running around there. http://www.network54.com/Forum/74182/
4412s are set up to be used as a single carb. They come stock with 73 jets and a 5.0 power valve. Running 3 of them will require jetting down some and leaning the idle circuits. Plugging the power valve requires jetting up to make up the fuel loss of the valve system. How much to jet up depends on the size of the power valve restrictions. I would start with 70s in all three and run a power valve in each one. If you can get to the idle feed restrictions, ya might be able lean them out a bit with a small wire in each one. The engines idle vacuum will play a role in how much to lean it out, so I don't have a clue of what size wire to start with.
The outside two carbs had the power valves blocked off to prevent to much fuel from being dumped in under low vac conditions (full throttle). I would start with the leaner main jets, screw your idle mixture screws all the way in then back out 1.5 turns each. Run engine till warmup, check plugs and driveability and jet accordingly. Also be sure to soak carbs in carb solvent overnight and blow out all the passages to remove any dried up fuel varnish.
A lot of fellas actually block the idle circuite of the end carbs all together. If I were building a tri carb setup, or as I have done in the past I would not run an idle circuit at all in my end carbs, and make sure that the center carb is fat enough to feed it until the secondarie carbs are ready to open up. Basically jet the center carb like it is only running on one carb.
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