I have a 75 F250 with a stock 360. The one exception being a 4V 600cfm Edelbrock carb. I have all ready insured proper timing. When at and idle with engine at operating temp it idles nice and smooth. The problem being, when cruising at a steady speed the engine stumbles. Mainly when driving through town at a lower speed like say, 25mph. It does the same thing while driving through a parking lot. Thanks for the help a head of time!

 

I would check the fuel pump...specifically the fuel pump diaphragm...they can get pin holes in them that induces a fuel starvation...typically starting at higher rpms and get progressively worse in the lower rpm's as the holes get bigger.

 

I would also check your vacuum advance for smooth operation. Make sure there is no play and no leaks in the diaphram.

Regarding the carb, you can call Edelbrock directly and they will tell you exactly what springs, jets, rods, etc to use for your setup and altitude, and where to set your timing, etc.

 

<p>How does it do at WOT?</p><p>Sounds like it's coming into the power circuit too quick. On a Holley, the power valve would be for a vacuum value that is too high. Not sure what an Edelbrock does for a power circuit.</p><p>What's the vacuum at idle? And, for a stock 360, you could bump the advance up quite a bit to improve the vacuum if necessary.</p><p>&nbsp;</p><p>&nbsp;</p>

 

How did you ensure timing is correct? Not sure if that particular engine is immune, but lots of Fords have dampers that can slip off their clock axis. Timing marks and settings will be erroneous. Common problem. Not doubting your ability here, just clarifying for others in the future.

 

<p>The FEs are NOT immune to the dampener ring slipping </p><p>&nbsp;</p><p>&nbsp;</p>

 

kind of like a Q-Jet, use metering rods and springs.

 

Edelbrock carbs don't like more than 5.5 psi fuel pressure. A stock Ford fuel pump runs about 7psi....I think. Too much pressure at low speeds causing a rich stumble?

Just a thought.