Runs better with vacuum leak

71 challenger driving me crazy with nothing but problems this year. Got the charging issue figured out then had start issues. New distributor runs fine but I was checking vacuum for timing at the brake booster. When I pull the cap it smooths out.

I've never noticed that before and trying to figure out the issue. Could the carb be too rich? New plugs helped previous hard start and smoothed it out but I just want to drive this friggin car!

I had a late 70's Chevy 4x4 that ran better with a leak, drove it like that for years. I'm sure someone here will have some ideas on how to fix your car ....but if it runs with the leak and you really just want to drive close the hood and go.

OK so it idles better with a vacuum leak, how about cruising down the road? It may be too lean and damage things. Is you vacuum hose coming off carb base affecting all 8 cylinders, or just the #8 intake runner affecting only one cylinder?

What do you have for a carb, camshaft, compression ratio, leak down numbers, tell us about the whole engine.

Is you power valve bad, cam to big, idle speed too low, fuel pressure too high, ignition system all goofed up? here we go, the snowball is picking up speed.

Haha thank you. I will touch base in a bit, installing trim in basement.

It sounds like you may have a issue of hot fuel boiling over into the motor when you shut it off, that will make them hard to start You will have to grind on the starter and hold the throttle wide open to get it to start and run if that is the problem. I've had that problem recently with todays crud they call gasoline One way to verify that problem is to remove the air cleaner after driving it far enough to get the motor up to temps. and heat soak the engine compartment and watch for fuel mist coming out of the top of the carb. from the boiling fuel. Have you tried leaning the idle mixture screws down enough to get the motor to sart to die? If not I run my motors as lean as possible on the idle circuits, adjust the screws slowly inwards. closing them, to make it start to slow down on the idle RPM and then add 1/8 to 1/4 out to make it richer richer A leaner motor is way happier than a rich or fat motor will be

If you are running the vacuum advance, AND depending on where it is hooked up ( IE: manifold or ported)_you may have too much timing at idle thereby creating a misfire. The distributor change may have impacted this. Creating a large enough vacuum leak would lower the manifold vacuum there by retarding the timing

Other wise I would go for thee mixture adjustment.

We know nothing of his combination. Any advise is just a WAGuess at this stage.

I do have a miss that I am getting to the bottom of. At the moment, I need to get rid of the old fuel and start fresh.

I have a stroked 360, .30 over, eagle crank and rods with Keith black pistons. I need to find my cam card but I believe I ended up around 10 or 9:1

750 edelbrock

Cr ran fine for me but I got into my charging problem, then the starting problem which is fixed. New plugs, old were fairly black.

My fault for the car sitting so much but that's what happens when your house was built right after the civil war....

Old fuel will make it difficult to solve anything. How much idle,vacuum, at what RPM does it idle hot? What coil and ignition?

Yes, fuel is my first fix. Car ran great before the charging issues. Stock coil, and I have a known good electronics box on it. Low,idle around 900 and it was bouncing around 15 vac