...for racing. I got two of em, one bored sixty over with no core shift, align bored with steel splayed main caps. I was gonna use the stock crank(10/10 & steel!) with H beam PF steel rods & KB hyperutectic pistons for a 412 ci package. I'm thinking now of a stroker in the range of 427+ ci. Problems seem to center on the small base camshaft & rod bolt clearance which can be accomadated, barely! My question is the durability of the 400 block bored to this tolerance. When a higher compresion like 13:1+ Mahle pistons is considered, FF H beam rods NOS & 8000 RPM my concern is block fatigue. Even if I fill the lower part of the water jackets with block filler a combo like this may well tweak the block & my wallet. I got a hot deal on it as the block was free as well the machine work. Problem is a GM rocket block or after market block will be consideribly stronger, & cam & block clearance problems are gone, plus even bigger ci combos. Cost shoots to the moon also!!! Comments welcomed!