So I just put in a 302/c4 combo edelbrock carb 600,f303 cam,afr heads air gap intake holley fuel pump regulated to 6psi, HEI Dizzy.....Anyway my problem is off and on I can pull up to the stop light and it idle like a dream take off nice just coastin THEN! I pull up to the next light it's idling like **** and when I take off it get really loud and accelerates like **** give it 1/2 trottle and it just gets louder the 3/4 trottle and it breaks loose and flys.....Now it does the bad part more than the good....I have changed carbs to one I know that was perfect....same thing and I changed the plugs gapped them to .055 still no luck I have looked at this car everyday for a few weeks now Its all a blur I need some/any input thanks!!
Well sounds like you have a damn sweet engine ! With those heads and cam it should run like a scalded dog ! Question , did you change the carb with the same brand and size carb or different size and different brand ? It really sounds like a fuel problem but if it acts the same way with 2 different carbs the odds of 2 carbs being bad doesn't usually work . Have you gotten a tank of fuel since all this started ? Are you sure the fuel pump is good all the time ? Now when it runs like **** , does it feel like it would be a carb adjustment or more like it's not getting enough fuel ? Have you had any problems before or is this a fresh engine ? Have the carbs been off a running engine for a while before you used them ? I would pull the top off the Edelbrock and check the accelerator pumps on each side of the carb to make sure one isn't sticking . I had that happen already to me and with all the **** that they are putting into the fuels today I am surprised we don't have more problems they we do . Edelbrocks get touchy with the Ethanol fuel we use . I have been having problems all summer with friends and customer having problems with their carbs and they all had Edelbrocks . I would also check the coil in the dizzy if you have a spare one or another dizzy that you can swap to see it that is the problem . What size carbs , cfm are you using Just a thought . Jim
I swapped the carb out with the same size off a perfectly good running car (exact same carb) I have run about 5 tanks of fuel ( it runs good on the freeway) The fuel pumps puts out good I'm sure I have a gauge on it...when it runs like **** it feels like its getting to much fuel?....I dont have a spare dizzy at the moment and its a 600cfm.... It feels like it just boogs down big time and I have to give it more throttle to get going once it breaks a certain point it runs decent
Well you sure don't have too much carb ! How about turning the fuel pump down to 4 - 5 lbs and see what happens . I think you said you are running it a 6 right now . I will agree it just sounds like too much fuel in the carb so maybe lowering the lbs will work . Carbs a funny like that . One runs good with 6 and the next wants more or less . With the cam and the heads you have there shouldn't be a problem on that end with too much fuel ! I would just p*** on the distributor right now . I am going to stick with a fuel problem . Jim
I turned the fuel pump down to 4.5 I pulled my carb off to inspect the base gasket (I could hear a whistle when I'd snap the throttle under the hood) and it appears I had a small leak I'm gonna put the new gasket on and see what happens.
OK that would explain the load and bogging down due to a vacuum leak . I hope that a cheap gasket is all it was ! Jim
I changed the gasket lowered the fuel pressure and advanced the timing a few degrees made a world of difference (I hope) I only got to put a few miles on he weather is real bad here.....I noticed now when I'm driving and punch it it sounds like it just dies then it takes off?? Thanks Jim!
Check your accelerator pump shot. Sounds like it's going lean. If it dies when you punch it, then takes off strong, it's taking in a huge gulp of air instead of fuel. Richen up the pump shot and try it again.
also make sre how the va***e advance is hooked up if it has one. you want it to advance the timing when you hit the gas not retard it. as in if im thinking right secondary va***e comes in when you hit the gas ported va***e drops out when you hit the gas.
I didn't see any comments about the ignition system - what sort of dizzy, coil and timing set-up got installed with the other hop-up parts? You'll want a hot coil and some vacuum advance to cruise around on the street too - otherwise, she'll be a guzzler. The 303 cam will want some more initial timing than a stocker for sure....and you will want a limit on the maximum (initial + centrifugal). my experience with the dizzy curves is that you sort that out first - then you get the carb to supply fuel to suit.
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