Topic: idling problem

[fred1750]

Well here is the info.

1969 302 v8 bored to 306, comp cam XE256H, standard replacement pistons, moly coated iron rings, stealth dual plane hi rise manifold, holley 4150, 570cfm carburetor, mechancial distributor with petronix module replacing points, hedman shorty headers.

Engine starts without a problem,  Cannot get it to idle, vacuum reading around 15 steady at 1800 rpm, dies when put into gear.

Had degreeing done at professional shop and preload set according to standards.

Is there a vacuum leak or a tuning problem with carburetor?

Need your thoughts.

Many thanks,

[Soaring]

I would first suspicion a vacuum leak.  Check all the hoses and connections carefully.  Try to screw the idle adjustment screws all the way in then out about 1 1/2 turns, then start turning them out 1/4 turn at a time until the engine smooths out.  Double check the timing.  That 302 is probably between 6 and 9 degrees BTDC.  If this hasn't improved it yet, then spray starting fluid around the intake manifold where the gasket meets the heads.  If the engine picks up RPM, then you need to replace the gasket.  If that is OK, then do the same thing at the base of the carburetor.  If the engine picks up, then replace the gasket under the carb.