new build '66 hot rod engine has ghost idle ?

[chris steineger]

We built a 2.5 liter hot rod motor using my original '66 911 cases. 9.5:1 compression. 2.7 liter heads w/ 34 mm intakes, E-S cam profile, 1969-71 stock distributor. Non Bosch standard 12v coil. Webers 40IDAs rebuilt w/ 40mm butterflys, 34mm venturis, 175 main jets, 170 air, 55 idle jets, F3 emulsions.

Have two problems:

Ongoing lean pops out the carbs when off throttle and lower RPMs.

AND, developing just in past week a "ghost idle". When engine is cold it idles about 600-700 RPM, but when warm idles at 1800 RPM.

Is this caused by vacum leak in the Webers ? Timing advance in the distributor ?
Can anyone provide advice ?

[Trackrash]

HBTDT. A couple of things.

You may find that the stock '71 dizzy should be recurved so you have something like 7deg advance at idle. Maybe even up to around 10 degrees. However you should limit the total advance to around 30 degrees.

I found that 55 idles were too lean for my carbs. You will probably need 60s or even 65s,

I also think 175 mains are on the rich side, but only way to know is to use an AFM gauge. But that won't cause your problems.

Make sure that your float levels are at the lower limit on the vile. And make sure they are all exactly the same level. This stuff they call gas nowadays will overflow when hot into the idle system.

Do you have the insulators under your intake manifolds?