I have a 240 carb off 76 buick 455 that is going on a bone stock 69 400 4speed 442.I ordered parts from Cliff and he sent me the parts he believes will be best suited for application.73jets,44L P rods,130-23 S rods and a 31-54621F2 needle & seat does anyone know what size this?and also where should the float setting be? Thanks, Chris
I use a high 1/4" float level on early carbs with the Big floats. I shoot for a 1/32" or two less than that on most other builds, especially if they arent going for long max effort pulls. A point to consider is that the higher the float setting, the higher the fuel level in the bowl, and the more likely we are to experience nozzle drip - all other things being equal.
If you are using a factory carb in it's stock factory application (rare) use the float level recommended in the charts. Of course this assumes that you have the correct size fuel inlet seat and correct OEM style float. If you can't find your part number or don't know, set it at 1/4" for fuel inlet seats up to .135". For "racing" and using larger N/S assemblies and high output mechanical pumps, especially if they are "dead head" you may need to lower the float a bit to prevent issues. For electric pumps dead-head you may also run into issues. For systems with a return in almost all cases the 1/4" setting will be fine even with fuel inlet seats up to .149". If you have an early carb with the short hinge pin and large float you may have to limit fuel pressure with the larger fuel inlet seats as they have a lot less leverage on the needle that later designs. You will see very "low" float settings for many 1975 and newer part numbers. They set the floats low because the factory used high pressure pumps and return systems to help keep the fuel cooler with the high heat created by the later "smog" engines loaded down with emissions. Also be aware that nearly every rebuild kit you purchase will NOT have the correct size fuel inlet seat in it, they typically range from .110" to .125". This screws the pooch for using factory float settings as it plays a role in the level of fuel in the bowl at any given pressure. So does the size and type of float used. Brass floats are heavy, and for early carbs a LOT smaller than the factory floats. This throws everything all out of whack when it comes to this topic. For Marine Q-jets use the factory recommended setting as they are application specific and almost always returning to their original home.....hope this helps some....
