[Nhowe0980]

I came across this forum while searching my symptoms on google and after reading a handful of threads on here it sounds like the kind of place I can possibly get some help. So here it is I have a 69 Chevelle with a 396, Iron heads with and extensive amount of porting work done to them by the machine shop, I am running a hydraulic roller crane cam 139011 (Duration 288/296, Lift .587/.610), edelbrock performer rpm intake, installed the performer 1411 which is a 750cfm with electric choke. The problem is the car is extremely rich at idle most of what I read says these carbs are known for being lean out of the box but I am not seeing that. Also when driving at about 1/8 pedal it runs good but when giving 1/4 throttle and up the engine falls on its face and back fires as if it it getting too much fuel. I do not have any type of 02 sensor hooked up to verify this curious what kind of input I can get. Also the vacuum advance is currently hooked up to the pass side port which is ported vacuum the driver side is manifold vacuum which side would be the correct one to use? Thanks in advance for the help. I am admittedly not a carb guy and am completely lost.
Thanks Nick

[spinn]

Deal with the rich idle cause of your cam. Only way to clean it up is with a load of inital timing. If the carb is functioning properly, a 750 edelbrock at baseline can feed that 396 well. That is how come my believe is that you have timing adjustments to make. Manifold vacuum can help you out with more inital timimg without a harder starter draw.

[Nhowe0980]

I have not had the chance to recheck timing. Just took it out for the first trip around the block 2 days ago from a complete frame off and noticed the doggy performance under load.

[mud.man.rj]

You are right with ported vacumn, not manifold vacumn, if everything seems to chech out well maybe check fuel pressure isn't to high it will also seem like the carb is to rich but is really just overfuelling by pushing past the float needle. Also check fuel cap to make sure it is venting, just loosen cap to see if it sucks in when opened. Could have a partly hung up float, their are two in every Edelbrock.

[techinspector1]

Edelbrocks will not tolerate over 5 1/2 lbs of fuel pressure. Adjust pressure to 5 psi. Alter ignition timing to provide 16 degrees at the crank and 22 on the weights for a total of 38.

[345 desoto]

How's your electric choke adjustment? That's what it sounds like...

[Nhowe0980]

Choke adjustment is good I believe all the way closed when cold with a little resistance on the flap. and when warmed up it is all the way open. I am gonna run down all these things later today or tomorrow and give you an update. Problem is I have to wait until snow is gone before I can take it around the block again and see if there is any improvement.

[345 desoto]

Try checking the float adjustment, too...