please please help with carb getting rich at WOT high rpm

[cudachris]

Hi folks,
this is my engine:
9.5:1 360
heavy port job on 587 J heads 2.02" 1.60" Valves
comp cams 0.545" 285/297 with matching springs
rpm air gap intake
800cfm edelbrock avs 1813s
tti headers 2 1/4 dual exhaust no crosspipe
new msd 6al new wires new mopar distributor 18° at idle800rpm 34°at2200rpm

got me an Innovative Motorsports lambda reading module from a friend so I welded a bung into my exhaust. Problem is, when I punch it, the a/f reading stays at 12.8 until 2500rpm then richens to 10.5 at 4.000 and stays that rich to 6000 rpm. I leaned out the secondaries from .404 to 3.92 but it didn´t really show. The engine feels strong, though. Is this too much carb or what is going on?
Thanks Chris

[rampage_82]

Has nothing to do with carb size... what is the A/F when cruising, or not under a load. When you're under a load or vacuum drops, the power pistons pop up, and richen you're mixture. I think you need to lean out the primaries, and run a little heavier spring.... See what that does for you...

[cudachris]

Thanks for your reply.
I spent a couple of hours tuning the carb, had several jet and neelde changes. Cruising is fine, power mode is fine, transition is fine, response is great, acceleration is fine, but at WOT it stays at 12.5 from up to 2500rpm then richens to 10.5 at 4000rpm and stays that rich till redline.

[aarracer]

CC

Are you oiling the metering rod pistons?

[chirorod]

could it be that ignition is breaking down at higher rpms? it it is, that could give you a richer reading.

[cudachris]

Ignition seems to work ok, at least the engine feels real strong at high rpm.
Oiling the metering rod pistons-never thought about that!
Thanks
Chris