Not sure about Holley's with sight glass. The screw types called for the fuel to "slightly" trickle out of carb when removed. So based on that I would start out with fuel just visible at the bottom of the glass.

Where it fuel level showing now in your carb? When driving, does car surges when driving at constant speed and then smooths out when you accelerate? After driving for awhile does car run erratic or even die when at stop light or stop sign. if all this is occurring, sounds like flooding issue.

 

Yea surges when steady smooths out on a accel. While idling the fuel is half in front glass and quarter in back glass. It will idle ok but only drive it a few miles. Didn't die

 

That's strange. Idiling ok, both cold and warmed up yet surging when driving. Making assumption acceleration while driving is gradual and not involving carb secondary. So, I would lower front bowl to same as rear and test drive. If better, lower it some more. Could also check to see if fuel continues to drip into carb after stopping. That would indicate debris or bad float seat.

 

Has the carb been apart? Why was the fuel pump and filter replaced? Did it run better before that?

 

Fuel pump not replaced just filter. It ran like crap when I first fired it up week or so ago. Put new filter on and it idles fine then. So today I took it for a drive and it was surging some. Carb never been apart.

 

Was just saying it was mechanical pump not elec.

 

How old is the gas in tank?
- Thinking maybe old fuel... but that should also be noticeable during idle (rough/inconsistent idle).

My nest guess would be a possible ignition timing issue.
What type of distributor are you running (points, HEI, electronic conversion)?
What is your initial timing at idle with vacuum advance (VA) disconnected?
If you have a may of measuring, what is your total mechanical advance (engine at higher RPM) with VA disconnected?
- What is your total advance (engine at higher RPM) with VA connected?
If using he VA, is it connected to a ported vacuum source (no vacuum at idle)?... or a full time vacuum source?
- Is the VA canister adjustable?

It is possible too much advanced timing is added from the vacuum advance canister and is causing the engine to surge at high vacuum levels. Most VA canisters on aftermarket HEI distributors can provide 20+ degrees of additional timing... on top of your mechanical timing.

P.S. A quick test to determine if the distributor's vacuum advance canister is adding too much advance and causing your issue...

• Disconnect the VA line to the distributor and plug the line.
• Drive your car, tying to duplicate the same "surging" condition.
• If surge goes away, issue is too much timing added by VA.

 

Without knowing ALL the history, I'm thinking fuel issues (and now float issues). That would be my initial focus like Railroadman & RifRaf said....

 

did you put a good quality sta-bil type add in your fuel at the end of last year. drain what you can an put it in your lawn mower. the add new fuel an hope that what an easy fix was.

 

Have new fuel In it because of thinking it was old fuel couple weeks ago. That's why I changed fuel filter. As far as timing I'm not sure on it. I paid a drag racer that owns a auto repair shop set it up for me. Hei with stock advance. Think its ported on vacuum. Hooked to port by the electric choke in pic

 

I think you have your VA connected to a ported vacuum source, but to confirm... is the vacuum line shown in the photo below connected to the VA canister on the dizy?

Try the quick test I had suggested in post #8.

• Disconnect the VA line to the distributor and plug the line.
• Drive your car, tying to duplicate the same "surging" condition.
• If surge goes away, issue is too much timing added by VA.

Can you also post a photo of your distributor's vacuum advance canister. I wanted to see if the VA canister is adjustable.

 

Pulled vacuum line plugged it drove car no difference. Pic of canister.

 

Pulled vacuum line plugged it drove car no difference.

Ok... it does not sound like too much vacuum advance.
Note: You do have an adjustable vacuum advance canister.

Maybe a vacuum leak somewhere???... that is more noticeable during the high vacuum + lean condition at cruise.
Be sure to check PCV valve, and power brake booster (if equipped).

You may also want to pull the spark plugs to see if there are any plugs that show signs of an overly lean... rich... or *oil/carbon fouled condition (*if there is an vacuum leak that is pulling oil into the intake from the lifter valley... or the carb is pulling in too much oil from the PCV valve). Be sure to check that all of the spark plug terminals are screwed on tight.

 

Did you lower the fuel level in float bowl?

 

I'm with RifRaf on the vacuum leak, especially since it was recently worked on. Nice, easy breathing and a good flashlight while reaching around as if going through recent work again - slow and easy, noticing everything.
Two cents on my car: I bought it at 7,000' elevation and brought it home to 1,000' elevation. It ran just like you described until I rejetted the carb (Goodwrench 350, Edelbrock carb, TH350 auto trans). It was getting too much air.

 

Pulled tha cap off, never had it off in 5 years. Found the plastic cover on harness and capacitor broken. Would this cause miss. Looked like a couple wires have been pinched.

 

Pulled the cap off, never had it off in 5 years. Found the plastic cover on harness and capacitor broken. Would this cause miss.

Possibly... but I would have thought the engine miss would be more consistent during various engine demands while you were driving your car if this was the issue.
From your description, it seems like your engine only misses during high vacuum level / cruise situations.

I would still replace the broken piece. Looks like you can get a replacement HEI wiring harness only.

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Be sure to also check the wires on the other connector that run to the magnetic pick-up.

 

I'm going to get a new harness and go from there. When I was spraying the carb cleaner looking for vacuum leak I sprayed in carb and engine idled up. I thought it should have bogged it.

 

I like to use a propane torch (turned on but not lit) instead of carb cleaner. Run it around the base and vac hose fittings, the most likely places for leaks.
If you have a vac leak the engine will somewhat smooth-out and idle-up. Both carb cleaner and propane are fuels and will somewhat correct the lean AF ratio when the fuel finds the vac leak.

 

Waiting on a hei harness a capacitor I noticed oxidation on two of the spark plug wire pins for lack of better word. It was on 1 and 5. Picture attached, what would cause it as you can see all others are like new.

 

Looks like heat, maybe from bad/intermittent spark issues. Could either be from poor quality parts or part failure from age? I'd ohm my plug wires and put a known coil in and triple check my connections and the ground on the coil. Also toss some dielectric grease on those posts. Either that, or swap in a DUI distributor, new wires(no cheapies) and plugs (ngk or delco) - that'll get it too.

 

I'm going home the wires if my meter works. Has new accel wires and new delco plugs in it.

 

I steer clear of those summit HEI distributors too. You see them on ebay rebranded as ATECH or RAMPAGE or ASSAULT. They usually promise 65k-90k volts yet sell for $100. Sometimes those can be janky right out of the box.

Oh yeah - a note on checking plug wires with a multi: I like to alligator clip one side into the boot and while holding the other end of the wire and probe, move the wire around in a bunch of different angles while I watch the multimeter screen. Sometimes laying flat, they'll show as being good, but once you kink them - there's a break.

 

So I checked wire number 1 it read 7.6 with my meter on 20k. Its 30 inch wire. Stayed steady at 7.6 however I moved wire sound right. 7.6/2.5 is 3.05 so that's 3000 ohms?

 

I always thought it needed to be set to a value above the 20k one, but maybe I'm wrong. The value should ideally be around 4-5000 Ω for quality wires - the higher the number, the more resistance in the wire.

 

Reading through this post, I keep thinking you have fuel problem.
When your done with the electrical tests if the issue is still present I have few suggestions.

Maybe in the float, although it idles fine. perhaps there is some gunk in the jets/ primaries fuel passages that only are used in medium throttle. The flat valve could be sticking shut causing fuel starvation , then a surge of fuel when it opens.
Are your butterflies tight? check the mount screws. If they are loose they can flop around causing fuel air and rpm control issues.
I believe you have checked the throttle linkages.... Is the throttle return spring correct? too strong and it slows the car, too weak and it can pick up speed without your input. either can cause fluctuations.
From what I read it only sputters at a constant speed, part throttle... that keeps me thinking its a fuel issue.
You have fresh gas, a new fuel pump and a new filter. you could also test the fuel pump output in PSI.
Just my thoughts. hope it helps, but really I hope you don't need it!

 

Still waiting on hei harness. Wires checked out good. I dropped float down a little, bottom of glass instead of middle of it. When I get it back together will get the propane out and check for vacuum leak. Might even throw the gauge on it.

 

I've used that method over the years.