413 carburetion issues

[al_wildman]

My 1962 Sport Fury has a V code (1964) 413 in it with next step down from max wedge heads, high performance cam, Weiand high rise and 2 600 cfm Edelbrock carbs (both are 1406s). Car runs great with a new Summit CDI ignition setup. I realize the carbs really need to be 500 cfm. My issue is an extremely rich idle that I haven't been able to adjust out. Fumes run me out of my garage even with all the doors open. The picture of the spark plug was made today after about a 10 mile drive at 45 mph with no WOT. Looks pretty normal to me.

Any ideas on how to lean my idle out a little bit?

Thanks
Dan Wilson

 

[Don Frelier]

First remove the covers for the metering rods, see if they are held down at idle.
If not then a weaker spring under the cups.
The plug looks real lean if anything.
Some say a real lean idle can drive you out of a garage.
A big cam in a 413 is going to stink it's just a matter of how much.

 

[al_wildman]

First remove the covers for the metering rods, see if they are held down at idle.
If not then a weaker spring under the cups.
The plug looks real lean if anything.
Some say a real lean idle can drive you out of a garage.
A big cam in a 413 is going to stink it's just a matter of how much.

So, you're thinking the vacuum may be too weak to overcome the spring? That may very well be true. Vacuum is only about 6 or 7 at idle and barely works the power brakes.

 

[Don Frelier]

You could test it at idle, just remove the springs.
See if anything changes.

 

[RJRENTON]

IMO....
The Carter - Edelbrock carb's idle and off-idle fuel feed source are in the carb's PRIMARY BOOSTER VENTURI in calibrated drilled orifices and are UNAFFECTED by changes to the primary metering jets and/or primary metering rods or step-up pistons or their springs. Those components only affect the fuel mixture when the primary booster venturii begin feeding fuel not before. These calibrated orifices are visable only when the booster venturii are removed from the body casting.
IF the carb's idle mixture is too rich, and cannot be reduced by normal methods, CONSIDER reducing the idle fuel mixture fuel feed orifice by 0.005". To increase the idle air bleed orifices, these can be increased by 0.002" - 0.003", but not recommended because of the the difficulty (almost impossible) to return to original dimensions if made too big.
IF it is suspected that the idle transfer slots are feeding fuel due to a high idle speed due to the cam, consider adding fixed idle air bleeds in the carbs primary throttle plates, say 0.125" diameter (possibly larger) to allow the throttle plates to close further but still allowing leaner idle mixtures. Too high air velocity thru the carb's primaries will often result booster venturii nozzle drip, causing excessive rich conditions at idle. Just my opinion of course.
BOB RENTON