Edelbrock 1405 carb. tuning/question?
(2010-05-30 12:01:10) 1. Says: I have a 73' 350sbc high performance application engine with a holley intake, hooker headers, HEI w/accell super coil. The engine is internally stock. The problem i have is once up to operating temp, when you shut it off for a couple of minutes and then re-fire, it acts like it is loaded up. you have to either crank till it fires or hold it wide open. I have rebuilt the carb and adjusted the a/f screws accordinally. The metering rods a sucked all the way down when at idle. I have also had it "fall on it's face" when you are cruising and cram it to wot. I'm am more concerened about the loading up problem though.Thanks2. Says: I have been using, working on and modding the carter AFB/Edelbrock carbs for over 10 years
Main probs. Float specs in older manuals are not right and stock settings aint right. Set floats at rest to 7/16" and drop to 15/16".. Measured at front tip of float, with gasket in place
*Tip* I use a drill bit or lenght of solid rod to measure floats. One is 7/16" in dia and other 15/16" in dia. Slid rod between air/gasket and float at tip. If theres any space, or if bit moves float up, it needs to be adjusted.
Also once you set one way (rest or drop) it could change the other so go back and check each setting 2 or 3 times
Next is fuel pressure. Some stock pumps will push the needles out of the seats. They like a max of 5.5 psi. Any more and its flooding to some degree. I use an adjustable pressure reg (holley dead head) and set mine to 5.25 psi
Then change the accel pump rod. Most engines likes the rod in the top hole of pump arm raher than middle like they come stock.
Most mild engines will run better with the pink or silver step up springs rather than factory orange springs. Check your vac at idle and divid it in half, then use a step up spring closest to that.
If you have 16" hg vac at idle, then you would need a 8" hg (silver) step up springs
Next would be timing, Alot of carb probs are really the result of the ign system. Check and set timing. On an engine like that I would want between 34-36* total timing.. So if you dont have a dail back timing light, set it at idle with vac advance lne un hooked to 14-16* before TDC
Now adjust your idle mixture screws. Use a vac gauge and adjust one screw at a time to get the highest vac reading you can.
The metering rods and jets are close to righ for most mild 350's like yours3. Says: sounds like too much fuel,try backing that adjuster back an 1/8 to 1/4 turn see what that does for you4. Says: are you sure the floats are set right? and as far as falling on it's face when accelerating check your engine timing, sometimes you need to up the timing a little to cure that. Tag: Edelbrock 1405 carb. tuning/question?