Carb Issues

[jps280zx]

Some that have seen my few posts understand I am new to the Mach 1 world. Also, I haven't had my hands in a carburetor for over 30 years. I have learned a lot about fuel injection especially in Datsun/Nissan Z cars and the other forums I have been on always yell at the newbies if they haven't done a search for their issues.

Well I tried, not sure I totally grasp the search feature for the site, but saw nothing related to my issue.
1970, 351c, 4v Holley looks like a total rebuilt has a sticker on it from a CA. shop, sorry not sure of the CFM. The literature I received when the car arrived indicated that the original Autolite had been rebuilt, doesn't atone for why a Holley is sitting their now - don't think a shaker hood makes a difference but it has that as well.

I think the car is running rich. Starts well cold, holds high rpms over 2k, step on accelerator to reduce rpms to idle, put it in gear and it stalls. The real issue is when you come to a complete stop and then move foreword - it takes light pedal action. Try stomping on it and it chokes badly with backfire in the carb. I got to drive the car for a few hours the other day for the first time. I have deep soot in the exhaust tips and my beautifully chromed bumpers are foggy.

Any assistance would be greatly appreciated. Haven't pulled the plugs to see if they are wet, but I am curious about the types of adjustments I should be making to the carbs. My Haynes manual is not very helpful as well. Thank you.

[JTS71 Mach1]

Most likely you have a carb that has cork gaskets between the metering blocks and the main body of the carb. And if it sits a long time they shrink and cover passages that they shouldn't. Which causes all kinds of issues such as you describe. There are manuals out there on rebuilding and tuning Holley's. Look in the back pages of Hot Rod, another place would be Hastings Book store, or possibly Amazon.com or something like that. Otherwise I would go find the oldest garage in town, with the oldest Mechanic, 40+ ought to do. And see if he knows anything about Holley's. But I can tell you with a little patience and doing a thorough job they are fairly easy to rebuild, with good results.
JTS 71 Mach1

[jps280zx]

Thank you!

[robsilveri]

Agree, plus its worth checking for vacuum leaks as well. My vacuum advance diaphragm was shot and so had a bad vacuum leak. I thought the off-idle stumble was due to the carb, turned out to be the vac-advance...

[JTS71 Mach1]

Another good thought! Everything has to work together. JTS 71 Mach1

[Steven Harris]

JPS,

It looks as if you have been given some good help.

Let us know how it goes for you which may just help the next one down the line. Plus we are curious.