This is a long thread for having limited facts known, just my observation.
First, did you check and measure the mating surfaces for flatness?
I don’t care what LCE told you, there IS a torque spec, and I don’t know who at LCE told you that but its stupid! The 22R intake manifold spec is 14 lbs. In MY opinion and MY experience that factory torque spec is too light. But, it is supported by a bracket... WHY do you think that is? After working on 3 Toyota trucks, 2 22REs and 1 22R since 1986, I don’t agree with the factory specs in several cases… again JUST MY experience.
If you are just “snugging” those bolts and nuts, the manifold and plate is GOING TO LEAK!! That manifold hangs off the head, it probably weighs MORE that the factory carb and manifold.
When I suggested to use Permatex High Performance Thread Sealer, I didn’t mean just on the threads.
Regarding the Alumaseal, I should have suggested how to put in the radiator… but it is too late now. It should only take about 30 minutes at freeway speeds to stop that leak…. BUT if the manifold and plate are moving due heat and vibration, and the torque pressure against those surfaces, with or with a gasket, is NOT sufficient - the Alumaseal may NOT work.
EDIT: By the way..... how many manuals can you show me or have you ever seen that refers to or specs torque for ANYTHING on a Toyota 22R engine at "snug"?