[boodlefoof]

Update:

I let the stuff cure for about 40 hours at room temp and then threw it in the over to bake at 200 degrees F for 2 hours. All looked good. I let them cool completely back to room temp and then set the oven to 400 degrees for the "post cure" per the instructions.

After a few minutes, I noticed a bit of steam coming from the oven. I popped it open to find that the Durabond had swelled slightly (about 1/16'' out from the intake manifold surface) and a liquid that looked like the binding agent was weeping from a pinhole that formed on that surface. I shut it down and let it cool. An inspection of the cooled part showed similar swelling and weeping from the valve side. The exhaust air boss fills looked fine. Thankfully, there don't appear to be any cracks in the heads around the exhaust crossover.

I called Cotronics and spoke with them about the situation. Their tech indicated that due to the size of the crossover pour it would take much longer to cure. Since it hadn't completely cured before I fired it to 400 degrees, the water in the mix started boiling off. I asked whether this could impair the product such that I would have to remove it and start over. He indicated that it would not be a serious problem and suggested I cook it for several more hours at 200, then pump more Durabond into any pinholes and cure again and the newly applied Durabond will bond to the old.

We will see how it goes. For others trying this, be forewarned. Let it cure for a long time under 212 degrees F before doing the post-cure!