I am in the process of building a mild 427 BB and was looking at the Keith Black pistons (p/n 227030).  I mentioned these to my machinist and he said that the closeness of the upper ring to the top of the piston could cause problems.  He said they would get too hot and lose their tension leading to early engine failure.  From what I read, they moved the ring up as a result of emmisions requirments and no other info was given.  Should I look for another piston or another mechinist? Should I go the extra and put in the forged pistons as extra insurance?  Mild build around 430 - 500 HP (like the original 435's) at the most.  

I do not think you will have a problem with those pistons I have used K.B. pistons in a lot of the engines I have built for customers as well as my self and never had any problems the only time I have seen the pistons fail is if the ring end gaps are set to tight. You will only need forged pistons if you are going to run N.O.S. or turn the engine above 6500 R.P.M.  

try this artical...

http://www.babcox.com/editorial/ar/ar110060.htm

it explains everything about what you want to know about the relocatiuon of the top ring.... and the heats issues affecting the temtion....  

Thanks for all the info, the article was very helpful.  If I read it correctly, the hypereutectic pistons are the way to go, I just need to make sure the clearances are correct, the final hone is with the 280 grit and make sure to use the correct size moly rings, following proper install procedures. Piece of cake! I'll probably be reading the article at least 2 -3 more times before I'm done!