That should be fine. I don't see how you could have caused that leak with the sender. It is more likely the gasket wasn't sealed correctly. When you remove the intake, see what type of gasket was used. The stock metal bath tub gasket should have silicone around each coolant passage on each end of the heads. If they used composite gaskets, make sure they used some kind of shield to prevent oil from being sucked into the PCV. I'd still be pulling the engine to send it back to the shop that built it. I can't see anything you did caused that kind of leak.
I'm not sure if it makes any difference, but it's listed as a 268/268 comp cam on Jegs. Is this any better or is it the same one you are referring to? https://www.jegs.com/i/COMP-Cams/249/96-203-4/10002/-1 Also, this is not intended for the strip. I need this to drive on a regular basis.
That is in fact the same cam. There are entire threads on why that cam is misplaced in a big block buick of any size, regardless of where it is intended to drive, street or race only.
Same cam, you are quoting the advertised numbers, 268/268, the .050 numbers are 218/218. The point is there are much better cams out there today. For one thing, that cam has the same duration for intake and exhaust. A split pattern cam is better, about 10* more exhaust duration helps out the poorer flowing exhaust port.
UPDATE: I didn't do it!! It wasn't the temperature sensor. Take a look at the attached pictures of the intake gasket area around the water port. I'm not sure if it's a bad gasket cut or a bad milling job on the intake. But, there's not enough metal behind the gasket to seal. Why is the metal milled away in this area? Is that normal? The gasket sits away from the port a little, which I think is normal, but then there's not enough metal behind the gasket to seal. Oh, the pictures are of the intake sitting upside down.
I know! Here's a picture of the other end of the same side of the intake. They did mill some material, but not nearly as much.
