Maybe I missed it....Did you do a DRY mock up with NO valley pan yet? Aftermarket stuff has slipped by with quality control mistakes before.
Seriously...To keep fiddling with different gaskets and sealers is totally pointless if the intake was cast or machined wrong.

I think i got it straightened out and didnt have to pull the intake back off afterall... I found 2 things that i didnt like and fixed both so not sure which one fixed it. I told you about spraying carb cleaner along the rail and it revved up right? Well i got to thinking that maybe the gasket between the carb and intake was possibly leaking and sucking that carb cleaner in and not the intake..so i pulled the carb off and that thick gasket was pretty rough..been used a long time, so i found a thin gasket to put between this thick gasket and the intake because that side of the thick gasket was in bad shape. Next, i checked the torque on the intake and it was only at 20 ft. pds..so i tightened it up to 40..Fired it up and she idled on her own!! I ran it for over an hour and drove around and all seems fine thankfully! I do appreciate everyones help with this, thats for sure!!! Now my next problem is finding another thermoquad base plate..the throttle shaft bore on the primary side on mine is worn and it whistles to beat hell when idling and is very aggrevating! Also, i cant get the primaries to close all the way against the idle screw because of this so its wanting to idle at 1000 rpm's..I can pull it back with my hand but it wants to go back up on its own..I think with the throttle shaft bore worn that its binding the primary plates just enough to do this.. This is a big primary thermoquad, wondering if i can use the base plate off any thermoquad as long as it has the big primaries? I know the top plates and center sections vary, but not sure about the bottom plates..This one is a 9077S.

That was too easy (sorry bad joke!). I'm glad it worked out WO haveing to pull the intake. Enjoy.

Glad it worked out. Especially appreciate the follow up. So many folks fix it and never share what was found. It helps the whole community of enthusiasts when one shares what fixes the problem. Now maybe I'll run out to the garage and look at my carburetor gasket.

if your goin to use the RIGHT STUFF you might as well just weld it on.

This reminds me of the story about the Marine Biologist that spent a week on a boat listening to whales squeak and moan, trying to interpret what the noises meant. After 7 days, he was ready to write up his report...THEN noticed the door to the cabin was opening and closing making the same squeaky noise he had been hearing all week.

Did that Marine proctologist STILL write up that report and bill the gov 500k$ ?

Been playing around with it tonight..all is well except for a minor little thing..with this SD intake, it has this very slight stumble off idle when stabbing the throttle wide open from idle..Its very, very minor..but it wasnt there with the original intake..any reason this single plane would do that where the dual plane iron intake didnt? Im not sure if maybe the big single plane may require even more pump shot than the dual plane did possibly?

The intake flows more air, the carburetor is the same. I say the pump shot needs to be increased. You are getting a momentary lean condition on tip in.

Some manifolds have bolt pattern for both types of carbs. If you are using a holley, that is the wide pattern. I have seen where one or more of the inner bolt pattern bolt hole, breaks through to the plenum. Huge vacuum leak and will make your engine run exactly as you are saying. I get a 5/16'x18 v1/2' set screw and put it in the leaking hole with red loctite.