Ok guys, so I got a 1964 330 F85 that had the low compression 2bbl engine from an older gent who had a backfire/carb-fire and no longer wanted to mess with the car.

I purchased an eledbrock performer intake, holley street avenger 570 carb, an ebay chineseium HEI and 1wire Alternator, Autolite plugs and cheap off-the-shelf HEI plugwires from Autozone.

I got everything on the engine and she cranked up first try. I removed the ballast for the ignition and removed the burnt voltage regulator and rewired everything..... so the car ran, well ran but was nothing spectacular as far as power is concerned. It had the factory 2.25" diameter single exhaust that was ohh so quiet.

Side note, during this time driving it I noticed a slight jerk when the car was driving... thought maybe it was the 2spd transmission but.....

Now I have installed the flowmaster dual 2.5" american thunder with H-pipe and that slight jerk while driving is now down right hard jerk.... and sounds terrible as you can hear what seems like the engine is missing. I couldn't really feel and dang-sure couldn't hear this issue with the OE exhaust.

So I take it to a friend's shop and he does some simple checks. All of my plugs are (according to him) just fine with a dry orangy-brown hue. He did not check compression at this time. He got in the car and rode with me and said it's a fuel delivery problem. He checked fuel pressure and it was fine. He then tried to check the float on the street avenger carb and found that (engine running, mechanical fuel pump pumping) when the bowl check screw was unscrewed, no fuel spilled out... he unscrewed the needle valve thing to adjust the float level and still no fuel spilled out.

At this point I was told to run seafoam through the tank and try to loosen up the floats that are causing my embarrassing miss/jerk from the engine. Well I have and no change.

When in park the car idles and revs fine. When in gear, the engine idles fine, but at onset of accelleration, the car will stumble and then accelerate decently. During hard acceleration, you cannot hear/feel any miss/jerking but when keeping a constant speed say 30mph or whatever, it's really jerky and sounds horrid.

Can anyone help me diagnose my problem and help me get this old gal running decent again?

Thanks in advance.

 

Accelerator pump? The new gas eats the rubber in a lot of the older cars,is the gas the same stuff as when you bought the car? The new stuff goes bad quicker,too.Just a few ideas. ---bil

 

I don't know... I'm not too knowledgeable when it comes to carbed cars. I installed both the intake and carb probably November 2009 and since then I've only gone through 3 tanks of gas.... so far I've only used shell premium. It's the only place in town that advertised 100% ethanol free fuel.

I borrowed a timing light from a guy at work today and used it tonight. Using his instructions, I checked the timing and it was like 1/2" left of the timing tab. I had to turn the distributor counterclockwise to put the timing mark under the left (of 3) gaps in the timing tab. It slowed the idle down slightly so I upped the idle abit on the carb.

Then I took it for a drive. It seems the choppyness and miss is about 70% less than it was. However.... it's got a horrible stumble off-idle. It wants to chug and die out then zoom it takes off. WTF?

Does anyone think the fuel bowls may be sticking or may be cracked and causing my problem?

Thanks!

 

Sounds like a lean off idle stumble. Might need more shooter or just a simple cam swap on the accelerator pump cam. Could also be a vacuum leak. Get a can of carb cleaner and spray around the manifold ports and base of the carb and see if the engine picks up speed at any time. If it does you have a leak. It's tough to diagnose things over the internet. When you described what you did with the distributor what you actually did was retard the timing. I believe timing on that car is 6 1/2 degrees BTDC. You need to clean off that timing tab so you can actually see the numbers on it. Retarding the timing even more like you did will only make the problem seem worse. Does the car surge when driving 30 mph (feels like it's going back and forth, not a steady speed?) You need to get a vacuum gauge and set the mixture correctly too. Vacuum gauge will also tell you if you have a vacuum leak or a bad valve etc. Find some local drag racer who knows Holley carbs and he can set you straight about how to set it up correctly.
I hate to be a jerk here but I've never had a Holley out of the box run right, they all need tweaking. Great carb once setup right but getting it setup right is another story.

 

Id agree with looking for a vac leak or acc pump.

 

Sorry I didn't include that info.... we used a can of staring fluid and checked for vacuum leak... no results there.

The timing is interesting... (I used a small brass brush to clean the tab and there were no numbers, it just has 3 indentions... looks like a 1 dimensional side view of a castellated nut) I figured it was way retarded when I began, it was approx 1/2" left of the tab all together... when I turned the dist. counter clockwise, the timing mark on the crank was under the left indention (3 indentions on the timing tab). So do I need to adjust timing again and move the crank mark under the middle I assume 0deg or even further to the right? On the tab... does the left mark mean retarded and the right mark mean advanced? I mean that's how I would read it- left to right on the number scale, or is it backwards?

I drove the car to work this morning and it runs better- much less jerky choppy driving..... but still has the off-idle stumble like it wants to die out. Even rolling at 20 or 30mph and giving it gas, it barbles down like it wants to die out and then comes alive.

Again, thanks yall.

 

Now it definitely sounds like an accelerator pump issue. When you open the throttle you introduce an big slug of air into the engine. The accelerator pumps job is to add fuel to that gulp of air so the engine doesn't stumble and fall on it's face. The main jets aren't fast enough to supply enough fuel initially so the accelerator pump does it. In fact if you have the engine off and move the throttle open while looking into the carb you should be able to see fuel shoot from the 'shooters' into the venturis. Can you see this happening? If not then the accelerator pump or the shooters are malfunctioning. Are the shooters clogged? Is the accel pump adjusted correctly? (.012 clearance between the accel pump lever and the carb linkage at wide open throttle)
If all the above is correct then you either have too small shooters (unlikely) or the accel pump cam needs to supply more fuel initially (in which case you need a set of pump cams, can be purchased as a set) You could also be too far retarded on your timing. I would advance your timing also to somewhere around 8-10 degrees initial. Although this is more then specified I'm sure after 45 years your timing chain is a little sloppy and has retarded the timing for you. You need to find the numbers on that tab or at least figure out which indentations are -2, 0, 2, 4 etc. You can't be guessing as to what those timing marks are and 1/2 to the left or right is not gonna cut it.
To help you out I looked up your timing specs. You should have 7 1/2 BTDC. Your timing tab has two marks on it 0 and 10 on either end of the tab. 0 on the drivers side and 10 on the passenger side. There is also an indentation in the middle for 5 but no number. I'd set it on 10 or close to it and start from there. 2 1/2 degrees difference from stock won't hurt a thing, especially after 45 years

Hope this helps to get you started.