I installed a new Holley carb pn# 0-80783c on my cutlass last fall, and since then I've been getting lean\surge on light accel and particulary at cruise between 30 to 45 mph. Above that speed the throttle is open far enough to get past it. This car is a cruiser and has'nt seen the high side 3500 rpm in 12 years and almost 77k.

A little about the car:

-completely stock 350\350 drivetrain
-2.56 open rear
-HEI ignition
-AC plugs gapped at .43
-about 36 degrees total timing

The high rear gear is key because it allows crusing at very small throttle openings. So much so that I think I may be driving on the idle circuit, as a 30 mph cruise sits at 1000 rpm. I've also noticed that if you pull it down in second gear above the problem speeds, and let it coast down my Flowmasters shut right up below about 1300 rpm.

Any help, suggestions, criticisms are welcome.

TIA

DAN

 

If you think it's lean why not richen it up or test it with a sniffer. One or two jets sizes will tell you right away if it's a lean condition. You didn't give us a whole lot to go on.

 

It also could be a vacuum leak, vacuum adv can or leaky vacuum line.

 

I have richened up the mains 3 steps from the out of box settings, it did improve, but I'm not sure that going so far from the stock settings was the way to go.

TripDeuces, what else do you need?

 

What stock setting? Was the car somehow adjusted for your car before putting it in the box?

 

The carb wasn't changed prior to installation, just went from box to car. The stock main jet is was a 67 and accel pump nozzle was a .028. It now has a 70's in the mains and .031 squirter. Has been thoroughly checked for vac leaks as well.