I can understand your concerns as I had those too. I tried everything to get it to stay cool but nothing seemed to do the trick so I finally took the step and drilled both holes.
Now I can say that with the adapter plate installed my truck has not gone over 180 degrees and the overheating problem has become a thing of the past. I highly recommend it.
And I didn't use gaskets the last time I installed it. I used the red color permatex and it worked great. Just let it dry for 24 hours before you add water.
