The Carburetor Shop. Eldon, Missouri. He has a website. TQs are his favourite carb.
Summit sells recond units. I ordered a 6000 series carb, 850, should be here soon. Reasonable price, too. Might be another way to go.
I called him he no longer builds carbs but can has complete kits for anything
He also has tquad metering rods but they are expensive
His recommendation for a tquad builder is San Diego Carburetor I called SanDiego carbs his price was $650!!!!!!