I have a 400 bored and stroked to 499, 12.5 to 1.
It's a great motor. Needed aggregate in the bottom of the block, but I run it on the street with no real heat problems until it gets around 100 degrees outside.
We calculated that we didn't have enough room for the extra thickness if we coated the headers in my car. You may want to check the thickness first ](*,)