ok, I took the freshly built 383 for its first good run up to the shop last week. I had some of the guys at the shop look at it to see what they think and if anything was wrong that I didnt see.

Well, there was an intermitent miss at idle that I couldnt figure out. One of the guys put both of his hands on top of the carb and it still ran! Both small vacuum ports on the carb are cap'd and the pigger one in the back is T'd for the PCV and brakes. So they only thing I could think of was something around the carb base/intake. So I took off the carb and put 2 gaskets in, someone told me it would help seal better. Hell, the motor sounds different now! In a good way though, it just sounds like its running better I guess.

So now I put my hands over the carb, it idles lower and kinda stumbles, but doesnt completely die. Should it, or is it kinda hard to not let any air in whatsoever through the carb?

Mixture screws are alomst all the way in and its still runnin rich, which is another indication that I still have some sort of vacuum leak.

 

Get some starter fluid and spray it around the carb & intake. Will let you know if you have a vacuum leak. You can also cap off all the vacuum lines for the brakes, etc. temporarily to see if it makes a difference. You could have a cracked hose or something disconnected somewhere.

 

Your problem is that you likely cause the vacum leak when u T'd the vacum port for your PCV and your brakes... It creates a internal vacum leak that u wont find when trying the spraying technique.. You will need sperate vacum sources for the brakes and PCV ...

 

where else is there another source for vaccum? Id assume somewhere on the intake, I just dont know which plugs are for coolant and which for vacuum. its a vortec performer intake.

I guess there would be one, then hook the brakes to the carb and PCV to the intake somewhere

 

Remove anad cap the lines for the PCV and brake booster for diagnosis. Vaseline can be very helpful for sealing suspected gasket area when trying to locate mysterious vacuum leaks.

 

you mean cap the back of the carb where the PCV port is? I thought I remember reading that it will run rich at idle because the PCv runs off of the idle circuit. I could be wrong though, just wanted to make sure about that.

 

BE CAREFUL WITH THAT STARTER FLUID!!! I was searching a leak on my, and caught the damned thing on fire! I'd use carb cleaner, or something less flammable - the starting fluid flashes up very very easily! Anything that is flammable will work, just doesn't have to be so damned flammable as starter fluid!

I found leaks around my intake - had to do an intake gasket set. I also used 2 carb gaskets, and it did help.