Edelbrock 1406 whistling

Guys,
My son's '74 Duster 318 has a brand-new Performer intake and 1406 electric choke 600 cfm carb (about a year old), which until today, was running great. When I started the car to go to work this morning, the engine took off like a bat out of hell, over-revving and rattling the valves and scaring the hell out of me.

In my panic, I kicked the gas pedal, and the idle dropped back down to normal...but after doing so, I began to hear a high-pitched whistling from the carb, and the idle became rough (like a plug misfiring).

Thinking it was a vacuum leak, I sprayed some carb cleaner around the base, and it had no effect on the driver's side. When I got to the passenger's side of the carb with the spray, the idle smoothed out and the car ran fine for a few seconds, and then went back to running like crap. I was late for work, so I decided to buy a new base gasket this afternoon, and fix the leak problem when I got home.

Well, I did that. I went to O'Reilly's and bough a replacement base gasket; I opted for a thicker Felpro type, since I hear that these 600's are prone to heat. I put the gasket on this afternoon, cranked it up, and the damn thing is STILL whistling. :cussing: I re-sprayed the area in question, and the idle picked up, et.al....the leak is still on that side.

My question for you guys is to ask opinions on what might be causing this...I read on the web that the airhorn (top carb body, not air cleaner) gasket could be leaking, or worse yet, those shafts on the choke side. I also read that the choke itself might be causing this, though I don't know how it could. And before anyone asks, my warranty ran out a year ago. angry9:

I've attached a pic of a 1406 I snagged off the web (NOT a pic of my carb, or of a Mopar), so I could highlight the areas in question: red arrows are the shafts, green arrow is the gasket....



Thoughts?

Rob